Residents of Abyei region have voted in an unofficial referendum over which country they wish to belong to - Sudan or South Sudan. Some observers forecast worsening tensions in the war-ravaged region.
"The vote is for the people of Abyei to choose their future," Luka Biong, spokesman for the Abyei Referendum High Committee, told AFP.
The fate of Abyei is one of the most important and sensitive issues left unresolved since South Sudan became an independent state in 2011, ending two decades of civil war in Sudan. Abyei is claimed by both Sudan and South Sudan.
"It has been proceeding well, it is being carried out in peace, and we have already seen large numbers turn out," added Biong, an academic and former senior official in South Sudan's ruling party.
The majority of 65,000 registered voters have already cast their ballot in the three-day vote that began Sunday, he said.
Both Khartoum and Juba have criticised the vote, with South Sudanese government spokesman Michael Makuei telling AFP it was "not a party to it" as it wanted a referendum "run according to the agreed system."
Experts on the region have also warned that the development could renew hostilities between the north and south, although relations between the two countries have been relatively peaceful in recent months.
Peter Schumann, a former director of the UN mission in Sudan, told DW that Abyei's decision to unilaterally hold its referendum was long overdue.
“The question is not why they voted on the referendum but rather why they have waited for such a long time, the peace agreement had foreseen that the referendum should have taken place in January 2011,” said Schumann.
Bashir pledges to work with South Sudan on Abyei
Sudan's President Omar al-Bashir on Monday pledged to work with his South Sudanese counterpart to settle the future of the Abyei region.
"I will continue with my brother Salva Kiir to reach a solution for Abyei that can bring satisfaction to the local communities there," Bashir said in a speech opening a new session of parliament.
Bashir said he and Kiir had agreed at a summit last week to form an Abyei police force and a local administration. They had already pledged in September to build that administration quickly, following a delay of more than two years since both sides first agreed to it.
Bashir met Kiir last week amid pressure to settle Abyei's future, but despite calling talks "fruitful" no breakthrough deal was achieved.
Bashir's latest comments came a day after the African Union Peace and Security Council said it was unable to visit Abyei on Saturday and Sunday because of "obstruction" by Sudan. It said Khartoum insisted that the visit be postponed for "contrived security reasons".
Schumann said it was too early to determine the impact of this referendum on the political dynamics in Juba and Khartoum.
African Union warns of return to war
AU chief Nkosazana Dlamini-Zuma warned on Monday that a vote in Abyei region was illegal and risked sparking a return to war.
Dlamini-Zuma said the "unilateral act is unacceptable and irresponsible" in a statement that "condemns this exercise in the strongest terms possible".
Patrolled by some 4,000 Ethiopian-led UN peacekeepers, the area is home to the settled Ngok Dinka, closely connected to South Sudan, as well the semi-nomadic Arab Misseriya, who traditionally move back and forth from Sudan grazing their cattle.
Luka Biong, spokesman for the Abyei Referendum High Committee, which is organising the vote for the Ngok Dinka, said that the majority of 65,000 registered voters have already cast their ballot in the three-day vote that began Sunday.
Misseriya reject referendum
The Arab Misseriya tribe, who traditionally move back and forth through the area grazing their cattle, have rejected the ballot.
"What happens in this referendum is none of our business. We don't care about it," the top Misseriya chief, Mukhtar Babo Nimir, told AFP.
Last week, he said the Misseriya might hold their own ballot if the Ngok Dinka went ahead, although he added that the tribe would not act without consulting the Khartoum government.
Schumann said Abyei was a region in which there were permanent residents, the Ngok Dinka, and others moving through, the Misseriya.
“But the Ngok Dinka have made it clear that whatever the outcome of the referendum, it will never affect the rights of the Misseriya to migrate south as they have done for centuries.
The United Nations and African Union have warned that any unilateral move could inflame tensions in the oil-producing zone and risk destabilising the uneasy peace between Sudan and South Sudan.