| Country | Disputes |
|---|
| Uganda | Tutsi, Hutu, Lendu, Hema, and other ethnic groups, associated political rebels, armed gangs, militias, and various government forces continue fighting in the Great Lakes region, transcending the boundaries of Burundi, Democratic Republic of the Congo, Rwanda, and Uganda to gain control over populated areas and natural resources; government heads pledge to end conflict, but localized violence continues despite UN peacekeeping efforts; civil conflict in Sudan has extended Sudanese rebel forces and refugees into Uganda and given shelter to Ugandan Lord's Resistance Army soldiers in Sudan; Kenya and Uganda are working together to stem cattle rustling and violence by Lord's Resistance Army along the border |
| Ukraine | 1997 boundary treaty with Belarus remains unratified due to unresolved financial claims, preventing demarcation and reducing border security; delimitation of land boundary with Russia is complete but boundary through the Sea of Azov and Kerch Strait remains unresolved despite a December 2003 framework agreement and on-going expert-level discussions; Ukraine protests Russia's construction of a causeway in the direction of Ukrainian-administered Tuzla Island in the Kerch Strait; difficulties with Moldova's Transnistria region complicate controlling border crossing and customs regimes despite concordance on the 2003 delimitation and customs protocols and OSCE assistance; has not resolved Romanian claims to Ukrainian-administered Zmiyinyy (Snake) Island and Black Sea maritime boundary despite ongoing talks based on 1997 friendship treaty to find a solution in two years |
| United Arab Emirates | because the treaties have not been made public, the exact alignment of the boundary with Saudi Arabia is still unknown and labeled approximate; boundary agreement signed and ratified with Oman in 2003 for entire border, including Oman's Musandam Peninsula and Al Madhah enclaves; UAE engage in direct talks and solicit Arab League support to resolve disputes over Iran's occupation of Lesser and Greater Tunb Islands and Abu Musa Island |
| United Kingdom | since Gibraltar residents voted overwhelmingly by referendum in 2003 against a "total shared sovereignty" arrangement, talks between the UK and Spain over the fate of the 300-year old UK colony have stalled; Spain disapproves of UK plans to grant Gibraltar greater autonomy; Mauritius and Seychelles claim the Chagos Archipelago (British Indian Ocean Territory), and its former inhabitants since their eviction in 1965; most reside chiefly in Mauritius, and in 2001 were granted UK citizenship and the right to repatriation; UK continues to reject sovereignty talks requested by Argentina, which still claims the Falkland Islands (Islas Malvinas) and South Georgia and the South Sandwich Islands; Rockall continental shelf dispute involving Denmark and Iceland remains dormant; territorial claim in Antarctica (British Antarctic Territory) overlaps Argentine claim and partially overlaps Chilean claim; disputes with Iceland, Denmark, and Ireland over the Faroe Islands continental shelf boundary outside 200 nm |
| United States | Prolonged drought, population growth, and outmoded practices and infrastructure in the border region has strained water-sharing arrangements with Mexico; undocumented nationals from Mexico and Central America continue to enter the United States illegally; 1990 Maritime Boundary Agreement in the Bering Sea still awaits Russian Duma ratification; managed maritime boundary disputes with Canada at Dixon Entrance, Beaufort Sea, Strait of Juan de Fuca, and around the disputed Machias Seal Island and North Rock; The Bahamas have not been able to agree on a maritime boundary; US Naval Base at Guantanamo Bay is leased from Cuba and only mutual agreement or US abandonment of the area can terminate the lease; Haiti claims US-administered Navassa Island; US has made no territorial claim in Antarctica (but has reserved the right to do so) and does not recognize the claims of any other state; Marshall Islands claims Wake Island |
| Uruguay | uncontested dispute with Brazil over certain islands in the Quarai/Cuareim and Invernada streams and the resulting tripoint with Argentina |
| Uzbekistan | prolonged drought and cotton monoculture creates water-sharing difficulties for Amu Darya river states; delimitation with Kazakhstan complete with demarcation underway; delimitation is underway with Kyrgyzstan but serious disputes around enclaves and elsewhere continue to mar progress for some 130 km of border; talks continue with Tajikistan to determine and delimit border |
