African Union mediators say Darfur's warring sides have failed to meet a 24-hour cease-fire ultimatum, putting the latest round of peace talks in Nigeria in jeopardy.
African Union officials late Saturday said military operations were still going on in Darfur.
They had asked the government and rebels to stop fighting on Friday in a bid to revive the stalled peace talks in Abuja.
AU spokesman Assane Ba said he received information from observers on the ground that clashes are taking place between army and rebel forces around the Darfur town of Labado.
"Fighting is still going on in Labado in the Darfur region, and helicopters are still firing,” said Mr. Ba. “So we have been informed, and now we informed the leadership of the AU, and from there we'll see what to do."
AU officials say that the current chairman of the organization, Nigerian President Olusegun Obasanjo, may now try to set up a meeting between himself and delegates from the warring sides.
Rebel spokesman Mohammed Ahmed Tugod has been refusing to take part in any negotiations because of the government action. "The Sudan government troops are still operating and their offensive military action is still going on,” he said. “The Sudan government is saying something but what is happening on the ground is actually the Sudan government is taking action, military action, in wide areas east of Darfur, and this is their intention - they want to sort out this issue by military means."
Sudanese government negotiator Najib Abdulwahab disputes that version, saying the fighting is taking place in a government-controlled area.
"What we are getting is that the rebels continue the escalation, continue the aggression in government-controlled areas,” he said. “They continue to block the roads, they continue to make the access of the international community to the needy impossible and for that reason the government is exercising its sovereign right of self-defense."
The 22-month conflict opposing mainly black African rebels against Arab-led government forces has killed tens of thousands of people and severely affected over two million others.