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Chapter 5


DEFENSIVE OPERATIONS

The immediate purpose of a defense is to defeat an enemy attack. Brigades perform a variety of operations in support of a division, corps, or JTF-level defense. They may attack, defend or delay across the full spectrum of the defensive framework as part of the division security, the main battle area, or reserve force. Brigades may also conduct offensive operations across the FLOT while the majority of the division or corps defends or they may serve as a ground tactical force in support of rear operations. The infantry brigade conducts defensive operations to defeat an enemy attack, gain time, concentrate forces elsewhere, control key or decisive terrain, attrite enemy forces, or to retain tactical objectives. The ultimate purpose is to create conditions favorable to assuming the offense. Future battlefields may be noncontiguous. Brigades are bypassed, penetrated, or encircled without loss of overall defensive integrity, but a penetration that threatens the integrity of the defense must be avoided. The enemy's main effort must be identified and met with sufficient force and firepower. Periods in which the defender can develop superior combat power are brief, so the concentration of forces must be rapid and violent. The brigade must be able to defend by attacking the enemy throughout the depth of his formations from positions that are mutually supporting and arrayed in depth. A cohesive defense plan may incorporate ambushes, reverse slope positions, rapid violent counterattacks, and depth to disrupt the enemy.

Section I
FUNDAMENTALS OF BRIGADE DEFENSE

Brigade defenses combine fires, obstacles, and maneuver to create and exploit the exposed flank and rear of the enemy. The brigade uses existing and reinforcing obstacles to disrupt, turn, fix, or block the enemy attack. The enemy is forced onto unfavorable terrain where he receives destructive fires from mutually supporting positions. Additional battalions attack the depth of the enemy. Attack helicopters overwatch counterattacking or delaying forces and attack follow-on echelons in depth. Electronic warfare destroys the enemy's ability to command and control its forces and synchronize its artillery and air support. Indirect fires delay and weaken enemy forces, causing them to change avenues of approach, and limit their ability to resupply and reinforce committed forces. Smoke masks friendly locations, isolates enemy echelons, degrades the enemy's target acquisition, and further slows enemy maneuver. A thorough understanding of enemy doctrine is critical to the success of defensive operations.

5-1. CHARACTERISTICS OF DEFENSIVE OPERATIONS

Successful defensive operations are characterized by preparation, disruption, mass and concentration flexibility, and security.

a. Preparation. To properly prepare the defense, the commander must be familiar with the abilities and limitations of the enemy. This includes the enemy's organization, conduct of attack, weapons systems, and equipment. The terrain must be analyzed in detail from all perspectives and then verified from the ground. Emphasis is on preparing and concealing positions, routes, obstacles, logistical support, and command facilities. Deceptions are planned and prepared, and local rehearsals are conducted. Supplies are pre-positioned, and security forces are emplaced. Counterattack plans to support the brigade's defense and to place the brigade on the offense are key to retaining the initiative. Counterattack routes must be reconnoitered, improved, secured, and the counterattack rehearsed.

b. Disruption. The brigade must disrupt the synchronization of the enemy's operation to counter his initiative, to prevent his concentrating combat power against a part of the defense, and to force him to go where the brigade wants him to go. Disruption is achieved by defeating or misleading his reconnaissance forces, impeding his maneuver, disrupting his reserves, neutralizing his fire command and control. circumstances, but all support, and interrupting his command and control. Defensive techniques vary with defensive concepts of operation aim at spoiling the attacker's synchronization. Strong security forces to defeat enemy reconnaissance, phony initial positions or dummy positions, and obstacles are some of the measures used to increase brigade security in the defense. Counterattack, counterbattery fires, obstacles, and retention of key or decisive terrain can be used to prevent the enemy from concentrating overwhelming strength against portions of the defense.

c. Mass and Concentration. The brigade commander must be able to concentrate forces and or mass the effects of fires at the decisive point and time. To accomplish this, he may economize in some areas, retain a reserve, shift priority of fires, and maneuver repeatedly to concentrate combat power during battle. Commanders must accept risks in some areas to concentrate for decisive action elsewhere. Obstacles, security forces, and fires assist in reducing these risks as forces are economized. The commander achieves concentration by designating a main effort, and he directs all other elements and assets to support and sustain this effort. He may also shift the forces by designating a new main effort as the situation changes. A commander weights the main effort by directing the tasks and purposes of supporting effort elements so as to create the conditions necessary for the main effort to accomplish its purpose. The commander may also weight the main effort by narrowing the sector, focusing counterattack plans in support of the main effort, assigning the main effort unit priority of obstacle preparation, giving the unit priority of indirect fire, and positioning the reserve to influence the main effort's area. Since concentration increases the risk of large losses from enemy fires, the concentrating forces must be masked by concealment and deception. The idea is to concentrate the effects of the forces, not to physically concentrate the forces themselves. Reconnaissance, surveillance, and security operations are vital to gaining the information and time needed to concentrate the brigade's forces and fires.

d. Flexibility. The brigade commander maintains his flexibility through detailed planning, sound preparation, organization in depth, retaining reserves and command and control. Flexibility requires the commander to "see the battlefield" to detect the enemy's scheme of maneuver in time to direct fires and maneuver against it. The commander does not limit his intelligence gathering efforts only to the forces in contact. He also concentrates on formations arrayed in depth. The enemy may try to bypass areas where the defense is strong. Hence, the brigade commander must ensure that he can detect and defeat the enemy along all possible avenues of approach. Aviation assets can be used to gather real-time intelligence. The brigade commander's plan must allow him to shift his main effort quickly if the situation changes while maintaining his synchronization. Also, alternate and supplementary positions are key to providing the flexibility he needs to effectively execute his defensive operations. Small reserves may be positioned near critical terrain or likely avenues of attack. Blocking positions, alternate positions, or even strongpoints may be established to deny the enemy a chance for a rapid breakthrough.

e. Security. The brigade commander must protect his force while in the defense. He normally establishes a security area. Security missions include screen, guard, and cover. However, the presence of a security force forward of the main battle area does not relieve the main battle area units from their own security responsibilities. All units must maintain security and contribute to the counterreconnaissance battle.

5-2. DEFENSIVE PATTERNS

The commander may use a variety of tactics, techniques, or procedures in the defense. The overall scheme must make the best use of maneuver and offensive tactics. Once the enemy has committed his forces, the defender's chief advantage is his ability to seize the initiative and counterattack over familiar ground. The defensive arrangements available to the commander include various combinations of mobile and area defenses. (FM 100-5 discusses mobile and area defense in detail.) Fire support considerations include the following:

  • Consider HPTs for each phase of the defense. During the counter reconnaissance phase, targets will differ significantly from those in the MBA.
  • Designate engagement criteria for each phase of the defense.
  • Plan the CFL close to the forward elements to allow rapid engagement of enemy units.
  • Consider NFAs around scout, COLT, and FO positions.
  • When emplacing FSCMs, consider the minimum safe distance of each weapon system.

a. Mobile Defense. The mobile defense aims to destroy enemy forces through decisive attack. A mobile defense uses a combination of offensive, defensive, and delaying actions. Divisions or larger forces normally conduct a mobile defense. A mobile defense is characterized by small forces committed to the defense of terrain and the use of a striking force to regain the initiative. It requires a committed striking force, resourced for decisive attack against an exposed enemy. The striking force must have mobility equal or greater than that of the enemy force. Infantry brigades may be used in mobile defense to hold strongpoints in restrictive terrain, or strike unprepared infantry from close proximity.

b. Area Defense. An area defense denies the enemy access to designated terrain for a specific time, rather than destruction of the enemy. It differs from mobile defense in that the bulk of defending forces deploy to retain ground. They use a combination of defensive positions and small mobile reserves. Commanders organize the defense around the static framework provided by the defensive positions, seeking to destroy enemy forces by interlocking fires or local counterattacks. Infantry brigades normally use an area defense when depth is not essential. The depth of the force positioning depends on the mission task organization of the brigade, and nature of the terrain. When an area defense is conducted in depth, elements in the security area identify and control the enemy's main effort while holding off secondary thrusts. Counterattacks on the flanks of the main attack then seal off, isolate, and destroy penetrating enemy forces. However, this is much more difficult to execute due to lack of flexibility that stems from early commitment of forces to decisive combat and the limited tactical mobility of light forces.

c. Fire Support Considerations. The key fire support considerations during a defensive operation include the following:

  • Consider HPTs for each phase of the defense. Targets during the counterreconnaissance phase differ from those in the MBA.
  • Designate engagement criteria for each phase of the defense.
  • Plan the CFL close to the forward elements to allow for rapid engagement of enemy units.
  • Consider BFAs around scout, COLT, and FO positions in the forward positions.
  • Consider the minimum safe distances of each weapon system when emplacing FSCMs.

5-3. OPERATIONS IN DEPTH

Forces at all levels must organize the defensive operations to facilitate the execution of the defensive missions. At brigade and higher echelons, the framework of the battlefield provides this organization. The enemy is engaged in three distinct areas--deep, close, and rear--but these engagements are planned and executed as one fight. Normally, brigades defend within the MBA or serve as a divisional reserve force. The defense framework (Figure 5-1) consists of the following complementary elements that synchronize the execution of the defensive plan:

  • Deep operations in the area forward of the FLOT.
  • Reconnaissance and security force operations forward, to the flanks, and to the rear of the defending force.
  • A main effort in the MBA.
  • Reserve operations in support of the main defensive effort.
  • Rear operations to retain freedom of action in the rear area.

a. Deep Operations. Deep operations support the commander's basic scheme of maneuver by conducting operations against enemy forces not otherwise in contact. They prevent the enemy from concentrating overwhelming combat power against the brigade's MBA forces. They accomplish this by separating the enemy's echelons and disrupting his command and control, CS, and CSS.

(1) Corps and division commanders normally fight deep operations. Intelligence assets are used to acquire high value targets whose destruction severely restricts the ability of the enemy to conduct offensive operations. Airborne, air assault, and ranger units are suited for deep operations. The brigade normally takes part in higher level deep operations as part of a deep attack or deep raid. It can also conduct its own deep operations as described in Chapter 2, Paragraph 2-11.

(2) Effective execution depends on careful planning and IPB. The IPB should disclose likely enemy command and control elements, artillery units, and logistical support activities. The FSCOORD, S3, and S2 must cooperate fully to ensure that emphasis on deep operations supports the brigade commander's concept of the defense.

(3) The commander must also remain aware of the arrival of any enemy follow-on echelon's lead elements into his area of interest.

(4) The division conducts deep operations to support the brigade close-in battle. Division information gathering assets, such as the LRSD, normally play a major role in obtaining essential information. A brigade preparing to conduct a deep attack or a spoiling attack must be given the main effort of the division's deep operations. Electronic warfare assets may target critical enemy lines of communication to degrade their command and control. Air interdiction and supporting artillery fires may delay and disrupt follow-on echelon forces to lengthen the brigade's window for offensive action.

(5) Combat service support operations are difficult in deep operations since they require extensive resupply and evacuation planning.

b. Reconnaissance and Security Operations. Reconnaissance and security operations are essential to the success of the brigade defense as well as other brigade tactical operations. These operations are characterized by reconnoitering aggressively to reduce terrain and enemy unknowns, by gaining and maintaining contact with the enemy to ensure continuous information and by providing early and accurate reporting of information to the brigade. The challenge at the brigade level is in resourcing these critical operations. The brigade has no organic, dedicated reconnaissance or security forces. In order to provide these functions in support of brigade operations, the brigade can--

  • Request additional reconnaissance and security forces (air or ground cavalry, LRSU elements, and division electronic intelligence gathering assets (such as GSR and REBASS).
  • Designate organic infantry units to conduct these activities such as infantry companies or platoons or antiarmor companies or platoons.
  • Place a subordinate battalion reconnaissance platoon as attached or OPCON to the brigade headquarters from the supporting effort or reserve battalion.
  • Task subordinate battalions to provide the required information in support of brigade activities.

(1) The reconnaissance considerations in the defense include the factors of OCOKA from a friendly and enemy perspective. Specific considerations are:

  • Battle positions, sectors, and EAs.

  • Counterattack routes.

  • Withdrawal routes.

  • Map corrections.

  • Landing zones.

  • Existing obstacles.

(2) The security operations forward of the FEBA include the following:

(a) A screening force maintains surveillance, provides early warning to the main body, impedes and harasses the enemy with supporting indirect fires, and destroys enemy reconnaissance elements within its capability.

(b) A guard force accomplishes all the tasks of a screening force. Additionally, a guard force prevents enemy ground observation of and direct fire against the main body. A guard force reconnoiters, attacks, defends, and delays as necessary accomplish its mission. A guard force normally operates within the range of the main body indirect-fire weapons.

(c) A covering force accomplishes all the tasks of screening and guard forces. Additionally, a covering force operates apart from the main body to develop the situation early and deceive, disorganize, and destroy enemy forces. Unlike screening or guard forces, a covering force is a tactically self-contained force (that is, it is organized with sufficient CS and CSS forces to operate independently of the main body). The covering force denies the enemy unchallenged observation of the main body and provides early warning and information about the enemy's dispositions while gaining time for the main body forces. As in all security operations, a covering force may be employed in the offense as well as the defense.

  • The covering force is deployed as far forward of the main body as the terrain and composition of the covering force allow. The commander's estimate determines the size and composition of the covering force. All types of infantry units can fight a brigade covering force battle. However, units with the greatest firepower and mobility are best suited for the job. Mobility facilitates employment in depth across the brigade front. Light infantry forces should normally receive firepower/nobility augmentation. Additional assets include artillery, engineer, MI, ADA, Army aviation EW, and chemical (smoke or NBC reconnaissance) units.

  • The size and composition of the covering force depends on the commander's estimate of the situation as influenced by the factors of METT-T. These factors are more important and complex, depending on the enemy's attack mode, depth of the area available for covering force operations, and time needed by MBA defenders to prepare for action. The covering force is normally tank heavy. A covering force operating in front of a division could consist of three or four tank-heavy battalion task forces or cavalry squadrons, with supporting attack helicopters, FA, ADA, and engineer units.

  • When the enemy is attacking, the covering force fires long-range direct and indirect fires to slow the advance. As the enemy advances, the covering force adjusts positions, and where possible, continues to fight or screen far forward. As elements of the covering force approach the MBA, battle handover is executed with MBA forces.

  • The covering force quickly passes through the MBA force. It may then assume BPs in the MBA or move to locations to rearm, reorganize, and prepare for future operations.

c. Battle Handover. The handover represents the transition of combat operation responsibility from the security force to the MBA force (Figure 5-2).

(1) Security forces hand over responsibility for the conduct of the battle to the MBA forces when the MBA forces are able to engage the enemy forces with direct and organic indirect-fire weapons. The headquarters that established the security force designates a phase line as the handover line. Based on recommendations by security force and MBA commanders, the higher headquarter's commander selects the actual location of phase lines, contact points, and passage points. When possible, the boundaries of the security force units coincide with those of the MBA units. Control measures are graphically reflected on overlays and are identified in the appropriate OPLAN, OPORD, or FRAGO.

(2) Security forces retain freedom of maneuver before passage of the battle handover line. The battle handover line represents the location where control of the battle is passed from the covering force to the MBA forces. It is usually 2 to 4 km forward of the FEBA. The MBA forces use direct fire and observed indirect fire forward of the FEBA to assist the covering force in its final delay, disengagement, withdrawal, and passage of lines. The transition occurs in some areas while the security forces continue to fight the enemy in others. The actual handover takes place at the time or event coordinated between the commanders or as directed by the brigade commander. Security forces must pass quickly through the MBA forces to reduce the vulnerability to fires. As security forces pass through the MBA units, they may assume battle positions in the MBA or move to locations to rearm, reorganize, and prepare for future operations.

d. Main Battle Area. Forces at the FEBA or within the MBA fight the decisive defensive battle. Forces are positioned in the MBA so they can control or repel enemy penetrations. The brigade commander adjusts the initial defensive plan based on information received during security operations. He assigns battalions sectors, battle positions, strongpoints, or a combination of all three in the MBA based on his force's capability and METT-T. The location of battalion strongpoints or battle positions usually coincides with or covers a major avenue of approach. The brigade commander weights the main effort by--

  • Ensuring supporting efforts are tied to the main effort.
  • Allocating additional ground maneuver forces.
  • Narrowing the sector.
  • Providing additional CS assets, especially engineers.
  • Providing priority of fires.
  • Positioning the reserve so that it is responsive to the main effort.
  • Limiting the number of tasks for the main effort.

(1) A defense may be structured around static, mutually supporting positions deployed in depth throughout the MBA. Obstacles are used to shape the battlefield and are routinely covered by direct and indirect fire. To enhance its effectiveness, the commander may hold out a large mobile reserve using available motorized and aviation assets and commit fewer elements to the initial MBA defense. The primary function of committed elements in such a defense is to slow the attack and fight it throughout the area. Mobile units then strike exposed enemy forces and engage those that have penetrated the defended area.

(2) Phase lines, sectors, battle positions, and strongpoints control the maneuver plan for the MBA defense as graphic representations of the commander's intent. The plan also provides for offensive maneuver within the defensive framework to take the initiative and exploit success. Spoiling attacks are planned to disrupt the enemy attack before it is launched. Counterattacks are conducted to defeat an attack after it has been launched.

(3) The brigade commander and staff must recognize the likelihood of penetrations of the MBA when they are fighting barge mobile forces. Penetration of the MBA and separation of adjacent units are apt to occur if nuclear and chemical weapons are being used. When this occurs, units must protect their flanks while striking at the enemy's flank in order to reestablish contact across areas of penetration.

(4) As the battle progresses, the brigade commander, in coordination with the division and corps, continues to fight the deep battle. He monitors events beyond the FLOT and follows the progress of enemy forces to prevent them from outflanking defensive positions or massing overwhelming combat power against committed forces.

e. Reserve Operations. The primary purpose of reserve forces is to provide flexibility and retain the initiative through offensive action. The best use of reserves is for decisive attack against an exposed enemy weakness or unexpected opportunity. Reserves can be used to conduct counterattacks, reinforce forward defensive operations, block enemy forces that penetrate the brigade's defense, or react to a rear-area threat.

(1) In estimating the situation, the brigade commander must consider the size, composition and mission of the reserve force. Mobility is vital to the successful employment of the reserve force. They must have mobility equal to or greater than the attacking force. Thus, the planning of mobility assets is critical.

(2) Positioning of the reserve force must facilitate rapid response to the most likely area of commitment. Considerations include the routes and time needed to get to the likely area of employment and the location of fire support.

(3) Air assault forces are well-suited for a reserve role. They can quickly reinforce positions to the front, to the flanks, or in depth. Air assault forces are also suitable for swift assaults against attacks in rear areas. (See FM 90-4).

(4) The commander may hold attack helicopters, if available, in depth and commit them as needed. They can respond quickly, thus extending the decision window for the commander. Their mobility and firepower often make them the quickest and most effective means of defeating surprise attacks and enemy penetrations.

f. Rear Operations. The corps and division commanders normally fight rear operations; however, the brigade's tactical operations include rear area operations. (See Chapter 8).

5-4. DEFENSIVE OPERATIONS PLANNING

The division commander's intent depicts the brigade's role in the division battle. The brigade commander must understand the corps and division commanders' intents and align brigade operations with the overall mission. The brigade commander likewise transmits his intent to his subordinates. The analysis of METT-T is performed as a part of the commander's estimate with continuous revision as planning, preparation, and execution of the defense occurs.

a. Subordinates are given the greatest amount of time to prepare since the effectiveness of the defense depends on time-consuming tasks such as reconnaissance, fire planning, preparation of positions, installation of obstacles, positioning of supplies, and improvement of routes.

(1) Warning orders and subsequent oral instructions are used to transmit the concept of the operation and commander's intent. Commanders do not wait for the complete plan to start preparations.

(2) To effectively complete the COA, the commander must evaluate the human factor. This evaluation may indicate that some units care better suited for blocking missions than for counterattack or for defending wider rather than narrower sectors. For example, a unit that has suffered several key leader losses may require more planning time to execute counterattacks, and it may be better suited for defending a narrower sector or for use in a supporting role.

(3) The status of unit training, morale, and discipline must be evaluated before fitting forces to the ground. The leadership status of various available forces also affect the final shape of the COA.

b. The brigade commander uses decision points developed through the IPB process to trigger the execution of contingency plans for his reserve and other friendly actions. The DST is an excellent tool for command and control in the defense. The reserve makes the best use of the defensive preparation time to rehearse each contingency plan in order of priority. Rehearsals are conducted, both day and night to the lowest level possible.

c. The maneuver commander must integrate and synchronize all CS assets to increase combat power. To effectively focus combat power, the commander designates the brigade main effort. Designating the main effort links each subordinate commander's actions to those around him providing cohesion and synchronization. As the maneuver commander develops his battle plan for employing maneuver forces, he must visualize how he will synchronize the FA, ADA, EW, engineers. Army aviation and CAS assets at the decisive time and place on the battlefield.

d. The defending commander structures the battlefield with an obstacle system that canalizes the enemy, enhances the effects of fires, and protects friendly positions and maneuver routes. Once the fight starts, the timely identification of enemy attack efforts and targeting of EW assets is accomplished by integrating all-source intelligence. The fire support plan must provide close support of maneuver forces, counterfires, interdiction of deep assets, and other fires such as SEAD. The plan must integrate FA, CAS, and Army aviation to increase its effectiveness. The ADA priorities must be determined and forces positioned to support the maneuver forces.

e. Without proper distribution of fires and clear, easily recognizable method by which to focus the fires at a desired point, numerous weapons will engage the same target while leaving others free to maneuver.

(1) Defensive fire planning is difficult because most of the available tools employed to distribute and focus the fires are fixed on the terrain. Regardless of whether we defend in sector or prepare battle positions, the weapons are static, emplaced while we sight our TRPs and build an engagement area. The enemy, however, is not static; they enter the area of operations and begin moving through it; at some point, if they are not stopped, they exit the area. The challenge in defensive fire planning is to increase the principles of fire control and to use static fire control measures to orient fires on the enemy while they continue to move.

(2) When obstacles are employed, choose a fire control technique that supports achieving the specified obstacle effect (disrupt, fix, turn, or block). How and when fires are focused and massed differ substantially if the intent is to turn the enemy into an EA or to simply disrupt him.

(3) Brigade commanders must ensure their subordinates make use of the following techniques in directing fires in the defense:

  • Dividing the EA.

  • Sectors.

  • Closest TRP.

  • Target array.

  • Fire patterns.

  • Target array quadrant.

  • Quadrants.

f. Fire support considerations include the following:

  • Consider HPTs for each phase of the defense. Targets during the counterreconnaissance phase can differ significantly from those in the MBA.
  • Designate engagement criteria for each phase of the defense.
  • Plan the CFL close to the forward elements to allow rapid engagement of enemy units.
  • Consider NFAs around scout, COLT, and FO positions in forward positions.
  • When emplacing FSCMs consider the minimum safe distance of each weapon system.

g. Planning must include counterreconnaissance. This includes all measures taken to prevent hostile observation of a force, area or place. As part of counterreconnaissance, security operations are conducted in all combat operations to defeat or mislead enemy R&S efforts to disrupt the enemy's synchronization. These operations include active measures designed to conceal, deceive, and confuse enemy reconnaissance elements (Figure 5-3).

(1) The brigade must integrate these measures into a detailed R&S plan designed to prevent the enemy from seeing and reporting the strength, composition, obstacles, and location of the brigade. The brigade's primary focus in counterreconnaissance is in providing and coordinating intelligence and fire support to help identify, fix, and destroy the enemy reconnaissance forces.

(2) The brigade S3 coordinates security efforts to ensure the brigade's operations are synchronized and executed effectively. He must use the brigade commander's estimate of the situation and the IPB process in planning security operations. All maneuver units must plan to counter enemy reconnaissance elements and patrols attempting to penetrate forward security forces. The CS and CSS elements and all CPs must establish local security and make the best use of hide positions.

(3) Units must make the best use of all available night observation devices. The S2 consolidates these efforts into the R&S plan.

(4) Unity of command is of vital importance. Within the security area, counterreconnaissance is a task with the same detailed planning requirements as any other tactical mission. It requires practice, synchronization, and communication to execute properly. It also requires a headquarters to command and control the various elements. The elements include both "lookers" and "killers."

(5) The security force should immediately be emplaced when the brigade completes an attack or moves to encounter mounted, dismounted, and stay-behind enemy. The security force should anticipate the enemy using RISTA platforms to gather intelligence on defending units. It consists of some or all of the following:

(a) Battalion reconnaissance platoon. These personnel are finders, not fighters. In security operations, they help locate enemy reconnaissance units for destruction by other elements or systems, such as calling for fire on enemy units they find.

(b) Maneuver units. Manning OPs and patrolling are normal infantry missions. Commanders should consider augmenting infantry with wheeled vehicles to increase mobility. Battalion-directed emplacement of PEWS can supplement other sensors, OPs, and patrols. If available, tanks or mechanized forces can be used to into a sector to establish a defense. It must be prepared assist with the security effort.

(c) Mounted antiarmor units. In addition to firepower and mobility, mounted antiarmor units provide a good long-range observation ability in all environments and conditions. The use of TOWs for security missions detracts from their ability to prepare for the defense.

(d) Remotely monitored battlefield sensor system. The REMBASS is available in some MI battalions. They should be emplaced along likely avenues of approach that cannot be covered by HUMINT or where redundant assets are to be placed in depth. They are most useful in covering dead space and broken terrain where observation would require more OPs or patrols than are available. The REMS can also assist in detecting attempts to breach friendly obstacles and in tracking enemy movements after withdrawal of security forces.

(e) Ground surveillance radar. When available, GSR can be used to assist in identifying enemy reconnaissance units during limited visibility. Since it is an LOS acquisition system, dead space must be covered by some other asset.

(f) Aviation. When available, air reconnaissance or air cavalry units can assist the counterreconnaissance effort. Air cavalry units can use organic attack helicopters, control indirect fires and CAS, or direct ground forces to intercept and destroy enemy reconnaissance forces.

(g) Field artillery. Responsive fire support is vital to successful accomplishment of the security mission. Based on the IPB, the FSO should develop a flexible fire support plan tailored to satisfy the commander's concept and intent. He should ensure it is distributed to the leaders of the security force. Batteries must be positioned according to METT-T in the defense, and the FSO should try to range at least one-third of the conventional artillery range forward of the lead maneuver unit.

(h) Air defense assets. Air defense assets deployed forward with security forces are necessary to provide early engagement for the main body. Denying enemy RISTA ensures defensive preparations are not interrupted, and unit dispositions are not targeted. The primary consideration is the main body and ADA weapons. Sensors should be positioned to achieve early engagement based on the air portion of the S2's IPB.

(6) Deception measures can be effective, but they must be believable. Deception is based on IPB and should have specific objectives. The skillful emplacement of heavy concentrations of smoke and frequent repositioning of units are effective deception techniques. Commanders must always assume the enemy is observing and must create a false picture of the units' dispositions. The deception operation must not disrupt position preparation or remove too many resources from the main effort.

(7) Planning and executing withdrawal of security forces to the MBA are critical. Too often units underestimate the speed of an enemy attack and begin their withdrawal too late. Specific guidance on both engaging the enemy and moving is required for the security force.

(a) The withdrawal of the security force should be planned as a rearward passage of lines under enemy pressure. Units receiving effective enemy fires cannot move unless those fires are suppressed or obscured. Commanders must issue precise instructions that preclude decisive engagement and must provide illumination suppression, and obscuration.

(b) For withdrawal to the MBA, route recognition signals and timing must be coordinated between forward security elements and company teams in the MBA. Withdrawal must be planned for both daylight and darkness. If practical, full-scale rehearsals of the disengagement should be conducted to ensure timing and coordination are sufficient and understood. Uncontrolled withdrawal to the MBA may result in fratricide caused by the effects of friendly obstacles, direct fire, or artillery. Contingency plans are developed for security units that are bypassed by enemy forces.

h. The commitment of the reserve may be the brigade commander's most critical decision during the defense. It is the most immediate way the brigade commander can influence the battle. Early in his planning, the brigade commander makes decisions concerning the size, composition, and mission of the reserve. A major purpose of the reserve is to retain initiative through offensive action. Other tasks of the reserve are to--

  • Reinforce the defense of committed units.
  • Contain enemy forces that have penetrated.
  • React to rear area and flank threats.
  • Relieve depleted units and provide for continuous operations.

i. The brigade commander may require his subordinate battalion commanders to obtain his permission before employing their reserves. He may also specify the location of their reserves. The brigade commander should use METT-T to dictate the size of the reserve. The reserve must remain hidden until committed. This protects it from enemy attack and enhances the shock effect when it is committed.

j. In addition to designated reserve forces, the brigade commander attempts to establish a new reserve from the least committed forces as soon as the original reserve is committed. This restores his ability to influence the battle with maneuver forces.

k. Logistical support must be considered during the planning and execution phases of each operation. The S4 must understand the brigade commander's tactical intent so that service support priorities can be established and logistical operations planned to ensure the supportability of the operation. Real estate management of the BSA and plans to conduct operations against Levels I and II area threats must be incorporated into the plan.

Section II
CONDUCT OF THE DEFENSE

For the brigade to succeed, it must counteract the enemy initiative. Security, good use of terrain, flexibility of defensive operations, and timely resumption of offensive actions are key to a successful defense. The commander uses the defense to gain time; time is needed to ensure a synchronized defense. The commander organizes his defense based on METT-T analysis and the higher commander's intent. He decides where to concentrate his effort and to economize forces. The commander assigns missions, allocates forces and fires, and establishes priorities and CSS resources. A properly conducted defense uses all available opportunities to seize the initiative. Once the enemy attacker has committed himself and moved into the defended area, the brigade commander strikes him with powerful fires and counterattacks in prepared engagement areas. Brigade commanders organize the battlefield by assigning a nonlinear defense, sectors, battle positions, strongpoints, or a combination.

5-5. DEFEND IN SECTOR

A defensive sector is an area designated by boundaries within which a unit operates and for which it is responsible. Defend in sector is the most common defensive mission conducted by forward battalions (Figure 5-4).

a. Sectors may be used in both the MBA and the covering force area. They orient on general enemy avenues of approach. They are used when the situation is vague, when multiple avenues prohibit concentration of battalions, or when the brigade commander wishes to allow subordinate commanders the greatest freedom of action. Sectors are normally deeper than they are wide to permit the defending unit to fight the battle in depth. A commander must defeat enemy forces within his boundaries, maintain flank security, and ensure unity of effort within the brigade commander's scheme of maneuver.

b. Sectors give commanders of battalions the freedom to decentralize fire planning. It enables thorough planning of fires and obstacles. It allows the commander to allocate his forces to suit the terrain to plan in depth, and to fully integrate direct and indirect fires.

5-6. DEFEND FROM BATTLE POSITIONS

A BP is a defensive location oriented on the most likely enemy avenue of approach (Figure 5-5). Its location is based on factors of METT-T. Security forces may operate outside BPs for early warning and all-round security. Units plan to maneuver within the BP as opportunities for offensive action arise, if such action is in compliance with the brigade commander's intent. When using battle positions, the brigade commander should designate sectors in order to expedite clearing fires and delineate patrol responsibilities.

a. Battle positions are used when the brigade commander wishes to retain control over the maneuvering and positioning of his battalions, and when terrain is open with good fields of fire. They are normally oriented on a defined avenue of approach and in a narrow sector.

b. If the brigade commander assigns a battle position, he is giving the battalion commander specific guidance on where to position his forces initially. Battle positions are used as follows:

  • To control fires.
  • To place fires as the enemy approaches.
  • To block enemy avenues of approach.
  • To control critical terrain.
  • To organize where multiple positions can concentrate fires on one engagement area.
  • On clearly defined avenues of approach.
  • On routes into the defender's flanks.
  • For positions near potential enemy airborne or air assault landing zones.
  • For reverse slope and counterslope defenses.
  • To coordinate terrain for battalion CS and CSS operations near the BPs.

5-7. DEFEND A STRONGPOINT

A strongpoint is a fortified defensive position, which is used to shape and control anticipated enemy penetration into the defended area (Figure 5-6). This is the most restrictive form of defensive mission in that the brigade commander selects the precise location of the battalion defense and normally reserves withdrawal authority. It is usually prepared by a battalion to defeat an attack from any direction. A strongpoint is essentially a battle position that cannot be easily overrun or bypassed by tanks and that can be reduced by infantry only with the expenditure of much time, effort, and an overwhelming force. Strongpoints can be established in isolation when restrictive terrain is on its flanks. It may also be tied to defensive positions of units on its flanks. In all cases, the use of strongpoints must be integrated into the overall brigade plan.

a. A strongpoint in small urban areas, astride routes, or along avenues of approach may halt a superior the enemy. A strongpoint causes congestion and limits his maneuver, and is best used to set up a counterattack.

b. A strongpoint takes several days to construct and is constructed from inside out. It consists of an integrated series of well-protected fighting positions connected by covered routes/trenches and reinforced with extensive protective obstacles. A strongpoint is designed to withstand artillery fire strikes, and mounted and dismounted assaults. It focuses on fortifications and protective obstacles throughout the depth of the position.

c. The commander must consider the high cost (to include manpower, engineer support and barrier material) to develop an effective strongpoint. The force that establishes the strongpoint may become isolated or defeated in detail. As a minimum, they lose their freedom to maneuver outside the strongpoint. Other engineering requirements outside the strongpoint might need to be sacrificed since the strongpoint receives priority of enemy force. To be effective, it must be a surprise to personnel and materials.

Section III
OTHER DEFENSIVE OPERATIONS

The brigade may conduct defensive operations that require unique planning considerations. These include attacks perimeter defense, stay-behind or hide from the defense, reverse slope defense, forces, and defense against armor.

5-8. ATTACKS FROM A DEFENSE

While conducting defensive operations, the brigade must always be ready to assume the offensive. From a defensive posture, the brigade can quickly conduct either a spoiling attack or a counterattack. The key difference is that a spoiling attack is executed before the enemy initiates his attack, and a counterattack comes after the enemy attack.

a. Spoiling Attack. The spoiling attack delays, disrupts, and destroys the enemy's capability to launch its attack or commit a following echelon. Its objective is to destroy enemy personnel and equipment, not to secure terrain and other physical objectives. Spoiling attacks are not conducted if the loss or destruction of the force jeopardizes the ability of the command to accomplish its defensive mission. The spoiling attack has many of the characteristics of a hasty or deliberate attack.

b. Counterattack. The brigade may counterattack with either a reserve unit or a lightly committed forward unit. The brigade commander may initiate this operation after the enemy launches the attack, after identification of its main effort, or after creation of an assailable flank. The conduct of a counterattack is similar to any other attack, but timing is critical to synchronize it with the overall defensive effort. The counterattack force should take the initiative from the enemy and exploit success whenever possible.

5-9. REVERSE SLOPE DEFENSE

The brigade rarely conducts a reverse slope defense along its entire front. However, there may be situations where subordinate units or weapons systems maybe effectively employed on the reverse slope (Figures 5-7 and 5-8). The reverse slope defense can be used--

  • When the forward slope is made untenable by enemy fire.
  • When the forward slope has been lost or not yet gained.
  • When the terrain on the reverse slope affords better fields of fire than the forward slope.
  • When the possession of the forward slope is not essential for observation.
  • When failing to do so would create a dangerous salient in friendly lines.
  • When the lack of cover and concealment on the forward slope makes it untenable.
  • When seeking to gain protection from mass fires.
  • When surprising the enemy and deceiving him as to the true location of the defensive positions.

True reverse slope situations may be undesirable because they may rely excessively on frontal fires. The reverse slope effect can still be maintained using the alternative in Figure 5-9.

5-10. PERIMETER DEFENSE

This defense is appropriate when the brigade is not tied in with adjacent units and must hold critical terrain (Figure 5-10). A perimeter defense orients in all directions. The brigade can organize a perimeter defense to accomplish a specified mission or to provide self-protection.

a. This type of defensive operation can be used when the brigade elements are in assembly areas, behind enemy lines when securing an isolated objective, or bypassed or isolated by the enemy. It can also be used when the unit must defend in place, is in an airhead, or when it must prepare and defend from a strongpoint.

b. Maneuver elements of the brigade are assigned to defend specific portions of the perimeter. The width, depth, and type of force required for a given perimeter defense depends on the factors of METT-T. Positioning of forces must provide space for dispersing antiarmor weapons and CS and CSS elements. The perimeter line must take advantage of key terrain and obstacles while ensuring that the perimeter is defendable.

5-11. STAY-BEHIND OR HIDE FORCES

The main purpose of a stay-behind or hide force is to destroy, disrupt, and confuse the enemy. The force must achieve complete surprise. A commander may take advantage of terrain to hide an offensive force in a defense until forward enemy elements have passed his unit. Units bypassed by the enemy may be ordered not to break out immediately. The higher commander may capitalize on the unit's position and use it for offensive action in the enemy's rear. Stay-behind or hide missions are high risk and should be considered only after exhaustive analysis of METT-T. Stay-behind operations are usually conducted by battalions (Figure 5-11). The following points should also be considered when planning a stay-behind or hide mission.

a. The force should consist of enough combined arms, CS, and CSS elements to sustain its fighting capacity for the duration of the mission.

b. The return routes or axes for the force should be planned in advance, with rally points established forward of and behind friendly forces lines.

c. The force may be required to conduct a breakout from encirclement after completing its mission. After the breakout, the force may link up with elements of its parent organization or elements from other organizations.

d. The return routes for the stay-behind force must be the best covered and concealed routes available. Obstacles along these routes that cannot be bypassed should have guarded lanes or gaps. Stay-behind operations eventually require reentry into friendly lines or linkup operations, often in more than one location. These contacts must be carefully coordinated to prevent fratricide.

e. Camouflage, cover, concealment, and SIGSEC must be planned in detail.

f. Units may be employed using several techniques as hide forces. Some options are as follows:

  • Air assaults into enemy areas to establish area ambushes.
  • Infiltration to establish a position from which enemy command and control can be disrupted.
  • Remain in position as enemy units pass the hiding force's location.

5-12. MODERN DEFENSE AGAINST ARMOR

Infantry brigade sectors may contain approaches that armor forces can use. While these approaches are not normally suitable for major breakthrough efforts by large enemy armor forces, they may pose a major threat to the continuity of the brigade or division defense. If penetration by mounted forces occurs, adjacent units become vulnerable to attacks from the flanks and rear. These armor approaches usually cannot be defended by a linear array of forces. Such an array is vulnerable to being rapidly overrun or penetrated while being suppressed by massive artillery, smoke, and direct fires. To avoid rupture, the brigade arrays forces in depth on armor approaches (Figure 5-12). This requires narrower fronts, more forces, or both.

a. This disposition of the brigade contains a series of mutually supporting antiarmor battle positions on armor-restrictive terrain; they are protected by infantry and strengthened by obstacles. The forward positions are designed to block enemy infiltration by dismounted infantry and attrit armor forces. If certain positions become untenable during the battle, units may be ordered to withdraw according to previously prepared plans. The depth of the defense is derived mostly from the initial positioning of forces. Maneuver to gain additional depth may be limited.

b. Defense-in-depth dispositions are stronger against armor; but, they are somewhat more vulnerable to infantry attack or combined arms action directed against one position at a time. Therefore, when preparing antiarmor positions, emphasize all-round security and mutual support. Each antiarmor battle position should have:

  • Dug-in fighting positions with at least frontal cover. Positions must be continually improved as time and resources permit.
  • All-round defense.
  • Protective mines and other obstacles to make the positions as tank proof as possible.
  • Mutually supporting positions for antiarmor weapons, sited to achieve flank shots whenever possible.
  • Coordinated direct-fire planning in each EA to avoid fratricide with other friendly positions.
  • Covered and concealed routes for resupply or withdrawal.
  • Armor ambushes between battle positions to preclude mounted bypass during limited visibility.
  • Extensive patrolling during limited visibility to preclude dismounted infiltration.

c. When deploying in depth, the intent is to defeat the mounted attacker by confronting him at the same time with antiarmor fires from multiple positions as he attempts to maneuver around them. Mines, other obstacles, infantry positions, and patrols close gaps that, because of terrain masking or heavy woods, cannot be covered effectively by fire. The attacker is engaged at long ranges with fires from tactical aircraft, attack helicopters, and field artillery, and then by organic antiarmor weapons positioned to deliver fires at the greatest ranges from multiple directions. As the enemy closes, antiarmor weapons may move to alternate and supplementary firing positions within the battle position to continue firing and to avoid being bypassed. Fields of fire are cleared to fully exploit the range of all antiarmor weapons.

(1) Deploying in depth is appropriate when defending against an enemy possessing greater ground mobility (mounted or mounted and dismounted), when armor-restrictive terrain is available or terrain can be made armor restrictive for unit positions, or when the terrain throughout the sector allows direct-fire engagement of both mounted and dismounted attackers.

(2) When the brigade defends in depth it organizes and positions elements to mass antiarmor fires on enemy AAs from positions on armor-restrictive terrain. Examples of terrain for such positions are: villages or towns; steep hills or ridges; terrain that has been reinforced with artificial obstacles; terrain near unfordable water or marshes; terrain with large boulders or lava beds; or thick woods with large trees.

Section IV
LIMITED VISIBILITY OPERATIONS

Aggressive limited visibility defensive operations can break up enemy attacks and permit the isolation and destruction of smaller enemy formations. With a detailed knowledge of the terrain and night vision equipment, brigade forces can operate effectively at night.

5-13. CONSIDERATIONS

Basic considerations in the night/limited visibility defense are as follows:

a. Patrols should be increased. Observation posts and early warning sensors are required for advance warning. Audio and visual recognition signals must be developed for use during limited visibility, particularly in a chemical environment.

b. Tactical plans must be simple. Units must train under limited visibility conditions. Execution must be decentralized with reliance on well-trained, confident, small-unit leaders. Detailed reconnaissance must be conducted during daylight as well to ensure execution of brigade plans. Movement takes longer during limited visibility; consider this when displacing units and planning counterattacks.

c. The psychological effect of limited visibility may require tighter formations and the need for special navigation skills. Smoke, snow, and heavy rain degrade most vision systems. Units may have to close in on the avenues of approach they are defending. Sensors and radar can sometimes lessen the effects of snow and rain.

d. The changing of natural and man-made battlefield conditions during daylight affects visibility. Weapons sited to take advantage of long-range fields of fire and observation during good visibility may not be effective when fog, haze, smog, or smoke is present. Weapons systems and defensive positions may have to be repositioned, especially to cover dismounted avenues of approach and obstacles.

e. The plan for a night/limited visibility defense should incorporate the following:

  • Positioning night vision devices (including thermal viewers) where their capabilities are best used.

  • Using long-range detection equipment (radar, sensors, night observation devices) on well-defined avenues of approach as part of a detailed surveillance plan.
  • Repositioning forces to concentrate on the avenues of approach that the enemy is apt to use at night.
  • Increasing the number of scouts, OPs, patrol missions, and armor-killer teams forward on secondary avenues of approach.
  • Using nuisance obstacles and early warning devices along likely night avenues to slow the enemy and to provide early warning.
  • Using OPs and patrols to prevent enemy infiltration between battle positions.
  • Planning and rehearsing the required movement of units and the massing of fires on main avenues of approach.
  • Repositioning weapons to compensate for the disparity between day and night acquisition ranges.
  • Ensuring TRPs are visible throughout the night.
  • Planing illumination on or behind likely engagement areas.

f. Commanders can expect an attacker to use limited visibility conditions--

  • To conduct reconnaissance operations to locate the defender's weapons, obstacles, and positions.
  • To breach obstacles.
  • To move elements through gaps in the defender's coverage caused by reduced weapons' ranges.

g. The risk of fratricide increases during limited visibility operations. Situational awareness enhanced by the use of global positioning systems receivers, real-time tracking of units by TOC personnel, positive clearing of all indirect fires, and close coordination with adjacent units all contribute to reducing this risk.

5-14. SMOKE OPERATIONS

Obscurants are used by the commander to conceal friendly unit locations, screen friendly maneuvers, support deception, and disrupt enemy offensive operations. Obscurants can slow and disrupt enemy movement and deny selected routes and landing zones. By forcing the enemy to tighten normal tactical formations for command and control, obscurants can cause the enemy to present a better target. Smoke operations supporting defensive operations must be incorporated early in the planning process. Some considerations include:

  • Planning must be synchronized with the battle operating systems.
  • The smoke platoon must be included in the brigade/battalion OPORD for smoke operations to ensure synchronization of effort.
  • The plan for using smoke must be coordinated with the battalions whose areas will be affected by its employment.
  • Security must be provided to smoke elements to include fire-support arrangements.
  • The use of obscurants reduces the effectiveness of friendly night vision devices.



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