Rebel accusations that new government air raids killed 26 civilians in Sudan's troubled Darfur (search) region cast a pall over peace talks in Nigeria, where African Union (search) mediators struggled Wednesday to broker an end to fighting that has killed tens of thousands of people.

A Sudan army official denied the rebel report. Lt. Gen. Mohammed Ismail, deputy chief of staff of the Sudanese army, said there had been no new violence in Darfur, which the United Nations has said is site of the world's worst humanitarian crisis.

A spokesman for the rebel Sudan Liberation Army (search), Mahgoup Hussain, said the bombings occurred Tuesday and Wednesday in Allaiat, a town in eastern Darfur.

"It is still continuing," Hussain said. "Definitely this round (of negotiations) will not go well. It is not logical. You are coming here for peace, and you are bombing people over there."

Hussain, who said a pregnant woman was among the 26 victims, spoke at the end of a third day of peace talks that so far have failed to yield any agreement. The conflict has displaced 1.5 million people since it started in February 2003.

On Wednesday, about 100 delegates gathered around a large oval table at an international conference center in Abuja, Nigeria's capital. As on Tuesday, talks broke off early after the AU failed to get the two sides to discuss a long-term political solution for Darfur.

Hussain said his group wanted to see an agenda before any political discussions and needed more time to prepare its own position before agreeing to face-to-face talks with the government.

An earlier round of peace talks ended without a truce in September after rebels refused to sign a humanitarian accord giving aid organizations wider access to refugees. Rebels insist they will not sign the accord without an accompanying security agreement first.

Ahmed Tugod Lissan, spokesman for the Justice and Equality Movement (search) rebel group that also is attending the talks, was pessimistic Wednesday about the prospects for a negotiated settlement.

"The government has not shown any sign of good intentions in Sudan ... and this is seen by what is happening in eastern Darfur," he said.

Lissan said Russian-built Antonov aircraft belonging to the Sudanese government flew repeatedly Wednesday over the town of Towisha, northwest of Allaiat, trying to "intimidate people."

However, the planes did not drop bombs there.

Last week, rebels said at least 7,000 people were displaced by fighting in and around Allaiat. Sudan's army said soldiers were only defending their positions, and it denied using military aircraft there.

The crisis in Sudan's western region began when rebels rose up against the Arab-dominated government, claiming discrimination in the distribution of scarce resources. Pro-government militias called Janjaweed (search) reacted by attacking Darfur villages.

The United Nations said the conflict has claimed 70,000 lives since March — mostly through disease and hunger. No reliable figures are available for those killed by violence.

Nearly 400 Nigerian soldiers will fly to Darfur on Thursday to bolster an AU peacekeeping force that is supposed to number more than 3,000 soldiers, Nigerian army spokesman Col. Mohammed Yusuf said. About 155 of the peacekeepers are Nigerians.

In Berlin, German Foreign Minister Joschka Fischer said it was important for nations to support AU efforts, but he cautioned that "we know today already that the underlying conflict won't be solved with an end to the violence ... We face a lengthy peace process in which difficult conflicts of interest, including access to the country's economic resources, will have to be addressed."