African Union-mediated negotiations in the Nigerian capital, Abuja, between the Sudanese government and Darfur rebels have been held up on their second day, amid accusations of an attack in the troubled province. The incident threatens to derail the overall talks, which have already been delayed by six months of deadlock.

Representatives from Darfur's rebel Justice and Equality Movement say government forces arrested three of their fighters in the city of El-Fasher, right in front of members of the African Union protection force.

They say they came under attack Friday, just as a new round of peace talks aimed at ending the civil war in Darfur was opening in Nigeria. The Justice and Equality Movement is one of two rebel groups fighting in the western province.

But a spokesman for the Sudanese delegation at the talks, Ibrahim Mohammed, told VOA he knew nothing about an attack.

"I have no idea about any clashes, since we moved and came to this point," Mr. Mohammed said. "We contacted back even early this morning, and they told me nothing about such clashes."

The opening of a second day of talks was delayed Saturday. AU representatives denied the delays were related to the alleged attack, saying only that consultations needed to be completed before negotiations could resume.

The United Nations' representative at the talks, Jan Pronk, at the opening ceremony Friday expressed his hope that this latest Darfur roundtable would bring some relief to the province's people, tens of thousands of whom have been killed in a civil war that broke out in early 2003.

"It's a matter of justice," he stressed. "It's a matter of freedom. It's a matter of independence. It's a matter of peace."

But, he said, there is only so much the international body could do.

"We, in the United Nations can help," he said. "We have ideas. But finally, it has to be, of course, the outcome of a domestic process."

Currently, the African Union, and not the United Nations, is in charge of security for monitors of an April 2004 cease-fire, which is routinely violated by rebels, Sudan's army, and pro-government militias, known as Janjaweed.

The African Union has around 2,300 troops on the ground to protect cease-fire monitors. Their limited mandate means they have little power to intervene to protect the civilian population that has been the target of most of the violence.

With the help of European Union and NATO airlifts, the African grouping is hoping to boost its presence on the ground to more than 6,000 troops by September.