Peace talks between the Sudanese government and Darfur rebels have stalled over the question of creating a no-fly zone over the area.
The talks resume later on Friday
Nigeria's President Olusegun Obasanjo, who is hosting the talks in Abuja, put forward a compromise, which called for a ceasefire on land and in the air.
The rebel groups agreed to the new wording late on Thursday; the government has rejected it.
The new stalemate comes as the UN warns of anarchy in the area.
United Nations envoy to Sudan, Jan Pronk, told the Security Council violence was increasing in the area.
"If this negative trend is not reversed it is a recipe for disaster," he said.
Mr Pronk called for a fast deployment of the newly-expanded African Union peacekeeping mission.
Some 1.6 million people have fled their homes since the conflict began.
Sudan's government refused to sign
peace deals with rebels on Friday, saying the accord drafted by
African Union mediators was too one-sided.
The talks which have gone on for nearly two weeks are due to start again at 1400 GMT.
AU mediators have described the security plan as the "best possible compromise".
As well as calling for a military no-fly zone over Darfur, the deal also demands the
disarmament of the pro-Khartoum militias.
Pro-government Janjaweed militias are accused of driving the region's black Africans from their villages, since two rebel groups began an uprising in February 2003.
The US describes the attacks in Darfur as genocide.
Aid agencies evacuating
The Security Council adopted a resolution in September which threatened oil sanctions against Sudan if it did not reign in the militias.
The UN's Mr Pronk says the government is not in control of its forces and fighting is breaking out in "more and more places".
"Governmental authorities are not able to exert a moderating influence, or they respond with untimely and even counter-productive measures," he said.
But Sudan's Foreign Minister Mustapha Osman Ismail lays the blame for the insecurity on the rebels, who, he says, increase their attacks ahead of Security Council meetings.
"I think the situation in Darfur generally is not that bad. It could be even better if the rebels were not insisting on violating the ceasefire," he told the BBC's Focus on Africa programme.
Aid agencies in south Darfur have evacuated some areas as clashes between rebels and the government continue.
Earlier this week, the UN criticised the forced removal of a number of refugees from a camps in Darfur. Mr Pronk said it was a "flagrant violation of international humanitarian law".
Khartoum defended the relocation, saying conditions in the camp were not good enough.
The Security Council, is due to meet in the Kenyan capital, Nairobi on 17-18 November, to discuss Darfur.