JUBA, Sudan (AFP) - Sudans flashpoint town of Abyei was ablaze on Monday with gunmen looting properties after its capture by northern troops, the United Nations said, as Washington demanded Khartoum pull out its forces. The UN Mission in Sudan, or UNMIS, warned Khartoum it was responsible for law and order amid reports thousands of civilians were fleeing southwards after northern Sudan Armed Forces troops and tanks overran the border town Saturday. UNMIS strongly condemns the burning and looting currently being perpetrated by armed elements in Abyei town, it said in a statement. The mission also called on the government of Sudan to urgently ensure that the Sudan Armed Forces fulfil their responsibility and intervene to stop these criminal acts. The UN said late Monday that northern forces had seized a key bridge on the southern border at Agok, a strategic route controlling access to the Abyei region from the south. Abyeis capture, in the run-up to international recognition of southern independence in July, has been condemned by the world powers as a threat to peace between north and south Sudan. Soon-to-be independent south Sudan also claims Abyei district, which has a special status under a 2005 peace deal that ended 22 years of civil war, and has called the occupation illegal. The SAF are still occupying Abyei and they continue to bomb, Deng Arop, the regions administrator who fled the violence and took shelter in Waw, a town almost 200 kilometres (120 miles) south of the disputed area, told AFP. He said that bombings of east and south Abyei proved the northern army intends to advance further south and that the continued indiscriminate bombing would only aggravate the humanitarian crisis. The United States urged Sudan to withdraw its forces from Abyei district. Princeton Lyman, the US envoy for Sudan, said the occupation of Abyei by northern troops is an extremely disproportionate response by the government of Sudan to an attack on a UN convoy escorting the troops last week. Meanwhile a UN Security Council delegation met with southern president Salva Kiir in the southern capital of Juba. Kiir, in sharp contrast to the delegations reception in the north, greeted members warmly, shaking hands with all. The members of the Security Council call upon the government of Sudan to halt its military operation and to withdraw immediately from Abyei town and its environs, French ambassador to the United Nations Gerard Araud said earlier. Senior US Senator John Kerry warned of the dangers of a return to conflict and told Khartoum it risked torpedoing a promised rapprochement with Washington. At this very moment, Sudan stands ominously close to the precipice of war, said Kerry, who chairs the influential Foreign Relations Committee. Abyei was granted a special status under the 2005 Comprehensive Peace Agreement, which requires both sides to keep their troops out until a vote on its future. The fighting has soured the mood in Juba. We fear that this can lead to something bigger, back to war, said businesswoman Mary Okech. Southern officials have vowed it will not impact the souths independence, due in less than two months. However, activists have warned of the severity of the situation. We always talk about proverbial forks in the road, John Prendergast, co-founder of the US-based Enough Project campaign group, told AFP. This is a real one between war and peace between the north and south. Prendergast, whose satellite project backed by Hollywood star George Clooney monitored a troop buildup in the Abyei area in the weeks before the fighting, warned any deal to resolve the conflict must put pressure on leaders. The European Union meanwhile allocated on Monday 200 million euros ($280 million) in aid to help south Sudan combat poverty when it becomes an independent state. Abyei was due to vote on its future in January alongside a referendum on independence for the south, which delivered a landslide for secession. But the plebiscite was postponed indefinitely as the north and south disagreed on who should be eligible to vote in an area where conflicted loyalties and land disputes keep tensions high.