FM 90-10 Chapter 4 Combat Support

CHAPTER 4 COMBAT SUPPORT

Military operations on urbanized terrain require special considerations pertaining to the provision of combat support. For example, field artillery and close air support, unless carefully coordinated, may actually prove counterproductive if collateral damage and rubble resulting from their employment impede subsequent maneuver. Increased engineer support is essential in both offense and defense; mobility and countermobility functions are especially critical. Signal support is basic to all combat operations. When fighting within a built-up area, the maintenance of effective and continuous communications may be difficult at echelons above company. On the urban battlefield, opposing forces are frequently hidden and protected by the readily available built-up terrain features. Close, violent combat requiring detailed coordination of combat support may be the norm.

The impact of urban terrain characteristics is most evident during the battle in built-up areas. This chapter supplements other doctrinal manuals by describing considerations applicable to combat support activities during offensive and defensive operations on urbanized terrain.

FIELD ARTILLERY

The missions of the field artillery are not changed by the urban battlefield. Positioning is critical because of mobility restrictions, limited availability of suitable areas, masking of fires by urban features, security, and enemy counterbattery. Within built-up areas, the direct fire role may take on added importance along with a more frequent use of the reinforcing mission.

OFFENSE

The force commander, after recommendation from his FSCOORD, makes the decision regarding the firing of a FA preparation in support of the maneuver to isolate the built-up area. The high probability of creating severe obstacles to future operations within the built-up area must be weighed. In addition, the requirement to preserve key facilities, such as civil communications, for future use must be considered.

Initially, the FA destroys enemy front line fortifications by massing heavy FA fires, neutralizes enemy artillery and observation by firing programs of targets, provides interdiction by creating obstacles, and covers the maneuver force's advance with smoke and fire.

When the brigade gains a foothold in the built-up area and begins to move through it, the FA moves forward by echelon to positions just outside the built-up area or within its large open areas such as parks. Consideration must be given, however, to the fact that these areas will be targets for enemy counterbattery/air. The batteries are positioned away from tall buildings and other masks. The effectiveness of FA during this phase may be limited because of restricted observation, masking, hard enemy cover, and the proximity of friendly troops to the enemy.

During the attack the maneuver commander at battalion, company, or platoon level may be confronted with hard targets that cannot be neutralized by organic or other supporting weapons. At this time a FA battery may provide one or two howitzer sections, depending on the situation, for direct fire. After the mission the howitzer sections return to the battery. If they do not, ammunition resupply may be a problem, and the field artillery's ability to mass will be decreased. In addition, there is the risk of losing individual howitzers. The supported maneuver units may become isolated and unable to extract heavy equipment and howitzers.

Besides continually neutralizing enemy artillery, rooftops and upper story windows are engaged with HE, fuze VT and Time, as well as smoke, to prevent enemy observation. Harassing and interdiction fires are used to prevent enemy movement in the streets and to deny rooftop observation, construction improvement, and use of withdrawal routes. During the advance through the built-up areas, FA frequently supports the maneuver elements of high-angle fire. However, because of the proximity of friendly and enemy troops, these fires require careful coordination.

DEFENSE

Initially, FA is located in battery position areas on the outskirts of the built-up area facing the enemy's approach. From these locations the FA engages the enemy at maximum range along avenues of approach. The object of these fires is to disrupt and slow the enemy attack and to separate enemy armor and infantry, thereby enhancing the effectiveness of friendly direct fire weapons.

At the appropriate time, FA displaces rapidly along predetermined primary and alternate routes to positions behind the built-up area. Once positioned, FA supports the fighting that will take place within the built-up area.

FA COMMUNICATIONS

The characteristics of built-up areas require that special consideration be given to the establishment and maintenance of FA fire direction communication nets. The range capabilities of FM radios which depend on line-of-sight may be significantly reduced. Site selection for antennas is critical. The use of relay stations or retransmission devices will frequently be required in order to maintain effective radio communication between FIST teams and fire direction centers. In many cases, forces may have to depend on the use of field wire nets that will be difficult to install and maintain. Because of these difficulties, appropriate supplementary signals, particularly pyrotechnic devices, are used to initiate, stop, or shift planned fires. (See COMMUNICATIONS, page 4-8.)

WEAPONS AND MUNITIONS

The 155 mm self-propelled howitzer offers its crew mobility and limited protection in built-up areas. It is effective because of its rate of fire and the 155mm projectile's ability to penetrate concrete (38 inches).

The 8-inch howitzer has a slow rate of fire, but its projectile has excellent penetration capabilities (56 inches of concrete). The crew must work in the open and is vulnerable to all types of enemy fire. The howitzer itself carries only three complete rounds and would have to be augmented with ammunition carried on another vehicle.

Artillery HE ammunition with concrete-piercing fuze provides an excellent means of penetrating reinforced concrete. Chemical rounds may clear a built-up area without destruction or may be used to canalize the enemy into a built-up area. High explosive, fuze quick, achieves excellent results against troops in the open. High explosive, fuze delay, bursts .05 seconds after impact and is good for penetrating light or medium bunkers and fortifications with overhead cover. High explosive, fuze time or variable time, is recommended for keeping OPs off rooftops and for discouraging movement in the open. Shell smoke obscures the enemy's vision, but troops should not move behind a smoke screen without some cover. ICM is effective against troops on rooftops and in the open. White phosphorous will start fires and is effective against materiel.

ENGINEER

During MOUT, divisional engineers may be attached in order to support dispersed maneuver elements (e.g., one engineer company to each committed brigade, one platoon to each battalion task force, and a squad to each company team). The majority of engineer manual labor tasks, however, will have to be completed by units with reinforcing engineer heavy equipment support and technical supervision. Frequently a divisional combat engineer company is reinforced by an engineer company of a corps combat engineer battalion assigned to the division.

Engineers perform the following missions during offensive operations:

Conduct technical reconnaissance to determine the location and type of enemy obstacles and minefields and make breaching recommendations.
Assist and train infantry units in preparation and use of demolitions for breaching structures or other obstacles.
Clear barricades and heavy rubble with earth-moving equipment to assist forward movement.
Destroy fortifications and strong-points that cannot be reduced with the maneuver unit's organic means with fires from the Combat Engineer Vehicles (CEVs) or hand-emplaced demolitions.
Use CEVs to destroy structures or clear rubble from routes of ingress/egress.
Clear minefields.

Priorities for the installation of mines by engineer elements are:

AT mines on armor avenues of approach.
AP mines.
Boobytraps.

NOTE: Authority for use of boobytraps rests with division.

Engineers perform the following missions during the defense of a built-up area:

Construction of essential obstacles and provision of technical advice to infantry units in the preparation of other obstacles using local materials where possible, to the front, flanks, and throughout the built-up area. Priority is given to construction of antiarmor obstacles on concealed and covered approaches to the defended area. Streets are barricaded to halt tanks at the optimum employment range of antitank weapons, to restrict/stop the movement of tanks and infantry, to separate attacking dismounted infantry from tanks, and to assist in the delay by inflicting casualties on the attacker. AT mines, with anti-handling devices, are employed with AP mines around and within obstacles and are covered with fires to make reduction costly and time-consuming.
Rubbling of buildings.
Preparation and execution of demolition missions as required.
Assist in selection and preparation and maintenance of routes to rearward positions.
Maintenance of counterattack and resupply routes.
Engineers must also be prepared, when required, to fight as infantry.

SUPPORT

ARMY AVIATION

When using Army Aviation in support of MOUT, consideration is given to the enemy air situation, enemy air defense capabilities, terrain characteristics within and adjacent to the built-up areas, and the availability of Army or Air Force suppression means.

Army Aviation support of operations within built-up areas includes:

* Lift for assault operations;

* Relocation of combat or combat support units;

* Resupply operations;

* Observation;

* Operation of sensory devices; and

* Radio retransmissions.

Missions for Army Aviation in support of built-up area offensive operations include:

Air assault operations to secure key terrain adjacent to the built-up area and to secure key objectives within the built-up area when the area is lightly defended or when enemy fires have been suppressed.
Employment of aerial weapons at long ranges to support maneuver units within or adjacent to the area.
Combat service support, command and control, communications, and intelligence operations.
Missions for Army Aviation during defensive operations of a built-up area include:
Employment of antiarmor aerial weapons at long ranges on approaches to the city or within the built-up area using terrain flight/pop-up techniques.
Rapid insertion or relocation of personnel (e.g., antiarmor teams and reserves).
Rapid concentration of forces and fires to meet unexpected enemy maneuver or movement of forces to rearward positions.
Combat service support, command and control, communications, and intelligence operations.

TACTICAL AIR SUPPORT

During MOUT, tactical air support can provide the ground commander with selective and discriminating fire support. Cluster bomb units, rockets, cannons, laser guided bombs, and electro-optically guided missiles are particularly suited for engaging hard targets.

The employment of tactical air support is dependent upon the following considerations:

The rubble and debris resulting from air attacks may increase the defender's cover while creating significant obstacles to movement of attacking forces.
The proximity of opposing forces will often require the use of precision-guided munitions and/or the temporary retirement of the forces in contact when supported by tactical air. The use of air weapons may be restricted by the presence of civilians or requirements to preserve key facilities within the built-up areas.
Limited ground observation will normally dictate that airborne FACs control strike aircraft in built-up areas if enemy air defense will allow.
The effects of weather will always be a factor. During offensive operations, offensive air support (OAS) is employed:
- To support the isolation of the built-up area by interdicting entry and exit routes.
- To support attacking units by reducing enemy strongpoints with precision-guided munitions.
- To conduct tactical air reconnaissance and provide detailed intelligence of enemy dispositions, equipment, and strengths.

During defensive operations OAS is employed:

To strike attack positions/formations and other concentrations of enemy forces outside the built-up area.
To destroy attacking formations as they approach the built-up area.
To provide precision-guided munitions support of counterattacks against fallen strongpoints.

AIR DEFENSE

Basic air defense doctrine will not change when operating in special environments such as built-up areas. The fundamental factors of mix, mass, mobility, and integration are applicable to the solution of the air defense problem in built-up areas.

The following factors apply to the employment of air defense units in built-up areas:

The enemy ground force's ability to maneuver is degraded in built-up. areas; however, enemy air will continue to operate unimpeded.
Built-up areas are static, easily located, and provide vulnerable targets for enemy high-altitude and tactical fighter-bombers. Additional targets such as principal LOCs, road and rail networks, including river bridges, radiate from built-up areas in today's potential battlefield.
The lack of good firing positions for long-range air defense missile systems in the urban environment may limit the number of deployed weapons. Weapon systems may have to be winched or airlifted into position.
Long-range systems can provide air defense cover from positions on or outside of the suburban ring.
Because the built-up environment will decrease line-of-sight capability, the commander must be prepared to change normal positioning requirements and control procedures. When communication relays are not used, line-of-sight is required between ADA elements.
Limited visual and electronic observation and close-in radar masks prevalent within built-up areas degrade the effectiveness of AD fires. Radar operators must, therefore, be trained to operate in extreme electronic clutter conditions.
Radar masking and degraded communications will reduce early warning time for both AD and non-AD units. AD control measures must be adjusted to permit responsive air defense within these reduced warning parameters.

MILITARY POLICE

MP operations in urban areas require continuous liaison and coordination with civilian authorities for the maintenance of law, order, and security.

Urban roads, waterways, and railroad terminals are usually critical choke points in the MSRs that sustain the battle. MPs are responsible for route reconnaissance, selection of alternate routes, convoy escort, and security of these vital LOCs.

MPs also secure critical civil installations (e.g., communication centers, government buildings, water and electrical supply sources, and sewer and subway systems). Employment of unattended ground sensors will assist in this task.

Refugee control, an inherent urban area problem, will be accomplished by MPs in close cooperation with civilian authorities. Also, straggler control operations may be necessary; enemy prisoners of war, detained by maneuver units or at critical installations, will be evacuated under MP escort as soon as possible.

see chapter 5 for further details.

CHEMICAL

Although the U.S. has rejected first-use of chemical weapons, friendly forces must understand their potential uses on the urbanized battlefield. Chemical munitions are area coverage weapons that can effectively penetrate strongpoints, bunkers, and buildings used for defense in built-up areas. Builtup areas tend to maintain higher chemical concentrations than the equivalent strikes in open or wooded areas. The employment of chemical agents can neutralize or destroy large numbers of defensive forces without damaging structures and equipment. This is especially critical in a built-up area where the criterion for success is often the capture of a structure or facility intact.

The multiple rocket launchers organic to Threat divisions are ideally suited for employing large concentrations of chemical agents against built-up areas. Threat forces may use chemical agents to neutralize a built-up area so that it can be bypassed. Defending forces must take specific defensive measures to minimize advantages accruing to an attacker using chemical agent-.

Chemical support may be required from smoke generator units for both offensive and defensive operations in built-up areas. In the offense, smoke can support the maneuver of combat elements and/or deception operations. Smoke employed in the defense obscures enemy air and ground observation, thereby limiting the accuracy of enemy fires and target intelligence.

Sometimes obscuration using smoke pots, generators, or artilledy smoke munitions should be considered to cover the withdrawal of defending forces or the movement of attacking forces. Artillery-delivered white phosphorus also may be effective on enemy forces by causing casualties and fires. Smoke should not be used when it degrades the effectiveness of aimed fires from friendly forces.

The use of smoke in built-up areas is affected by terrain considerations. Buildings cause wind patterns to be extremely complex. When covering a built-up area with a smoke haze or a blanket, it is essential that all buildings be covered. Failure to obscure tall buildings, towers, and steeples will provide enemy observers with reference points for placement of fires within the built-up area.

Maneuver units may also use smoke grenades to provide a hasty screen to conceal movement across streets and alleys or for signalling. M203-launched smoke grenades can be used to mark targets for attack helicopters or tactical air.

When authorized, riot control agents, such as CS and CN, can be used to drive enemy troops from prepared positions or, in the persistent form, to deny areas to enemy occupation. Riot control agents are incapacitating, with no lasting casualty effects. Therefore, they are effective when the avoidance of civilian casualties is a planning consideration. Against an enemy well trained in chemical defense, however, riot control agents will not be overly effective.

NOTE: The incendiary effects of both WP and the base ejection munitions in the litter and debris of the built-up area must be considered.

COMMUNICATIONS

MOUT poses special problems for all communications operations. Built-up areas distort radio wave propagation, and the limited availability of uncongested lines of communication make it difficult to move and install fixed station and multi-channel systems. Communications difficulties are particularly intense within built-up areas.

Frequency modulated (FM) and very high frequency (VHF) radios that serve as the principal medium for command and control will have their effectiveness reduced in built-up areas. The operating frequencies and power output of the sets demand a line-of-sight between antennas. Line-of-sight at street level is not always possible in built-up areas. Amplitude modulated (AM) high frequency (HF) sets are less affected by the line-of-sight problem because operating frequencies are lower and power output is greater. HF radios are not organic to the small units that will conduct the clearing operations. How can this be overcome? Retransmit the FM and VHF signals.

Retransmission stations in aerial platforms could provide the most effective means if they are available. Most likely, organic retransmission sets will have to be used. The antennas should be hidden or blend in with the surroundings so they won't be landmarks for the enemy to home in on. They can be concealed by water towers, existing civilian antennas, and steeples.

Wire can be laid while friendly forces are in static positions, but careful planning is necessary. Existing telephone poles can be used to raise wire lines above the streets. Ditches, culverts, and tunnels can be used to keep the wire below the streets. If these precautions are not taken, tracked and wheeled vehicles will constantly tear lines apart and disrupt communications. Alternate lines must be laid.

Messengers provide security and flexibility; however, once the battle begins, messenger routes must be carefully selected to avoid any pockets of enemy resistance.

Visual signals, such as arm-and-hand signals, take on added importance in this environment. They are excellent for calling for fire, lifting or shifting fire, and for indicating the seizure of buildings. Pyrotechnics, smoke, and marking panels are also excellent means for communicating, but they must be well coordinated and fully understood by air and ground forces. The noise of combat in builtup areas makes it difficult to use sound signals effectively.

The seizure or retention of existing communications facilities must be included in planning. Every effort should be made to prevent damage or destruction of these facilities. The local telephone system is already in place and tailored to the city or town. Its use by our forces provides immediate access to wire communications with overhead and buried cable. This helps overcome the problems encountered with radio and provides a cable system less susceptible to combat damage. Local media, such as newspapers, radio stations, and TV stations, provide communication with the local populace after the level of combat declines. Intact police or taxi communication facilities are also a possibility for a radio system tailored to the city with retransmission facilities already in place.

OTHER COMMUNICATIONS ONSIDERATIONS

Consider a few more steps that should be taken within the built-up area: park radio-equipped vehicles inside buildings for cover and concealment and dismount radio equipment and install it inside buildings (in basements, if available); place generators against buildings or under sheds to increase noise absorption and provide concealment; install wire through buildings which are still intact if they provide a good route; place antennas on roof slopes away from the enemy and knock holes in walls below rooftop level for directional antennas.