The chief of a Darfur rebel faction that refused to sign a peace deal for the war-torn Sudanese region said Friday he wanted to obtain further guarantees from the Sudanese government before committing to the agreement.

Abdel Wahid Nur said he wanted commitments from Khartoum in the areas of power-sharing, security arrangements and compensation to victims of the conflict.

"I will not sign the agreement without a supplementary document to address clearly our concerns," Nur told The Associated Press on the telephone from Abuja, Nigeria. He did not outline his specific demands in those three areas.

CountryWatch: Sudan

Four years of conflict in Darfur between rebel groups and government forces and the pro-government Janjaweed militias has killed at least 180,000 people and displaced more than 2 million.

Nur, who heads a splinter group of the Sudan Liberation Movement, said he had sent his additional requests to the Sudanese government and was waiting for them to accept it before he would sign the peace agreement.

He appealed to the Minni Minnawi, the main leader of SLM who signed the peace last week in Abuja, "to withdraw from the agreement, because it is not a comprehensive agreement for now."

Minnawi, who had flown to Chad to discuss border security and the repatriation of some 400,000 Darfur refugees there with the Chadian president, was not immediately available for comment.

However, he said earlier Friday that he was firmly committed to the peace accord, and was confident that Nur's faction and the smaller Justice and Equality Movement would reconsider their rejection of the deal.

"I think both movements will sign the agreement," Minnawi said on the telephone. "When it happens, it will be a very big victory for Darfur."

Minnawi, who heads the main branch of the Sudan Liberation Movement, signed the peace deal last Friday in Abuja, Nigeria, after a last-minute push from U.S. Deputy Secretary of state Robert Zoellick helped conclude six months of negotiations.

African Union Chairman Alpha Oumar Konare had said on Thursday he was confident Nur's faction would agree to the Darfur peace deal. Nur's acceptance of the treaty is important because of his broad support among the Fur -- one of the larger tribes in Darfur, which means literally "the land of the Fur."

The United Nations' chief envoy to Sudan, Jan Pronk, also said there had been several high level discussions this week to convince leaders from the dissident factions, as well as military commanders on the field, to accept the agreement.

"Broadening the circle of support for the agreement is the top priority," he said on the telephone from Khartoum.

"I would not exclude progress in that direction soon, it's a necessity that everybody understands," he said.

Darfur, a vast region of western Sudan, has been torn by violence since rebel groups made up of ethnic Africans rose up against the Arab-led Khartoum government in 2003. Arab militias known as the Janjaweed, said to be backed by Khartoum, have carried out a wave of violence against ethnic African villages and are accused of widespread atrocities. Khartoum denies backing the Janjaweed but has said it will try to rein them in since the deal was signed.

Ensuring the Janjaweed respect the cease-fire agreed last week is key to persuading Darfur rebels to comply with the peace deal, but there have been several Janjaweed attacks since then, said Pronk. "And I am afraid this will continue for some time," he said.

Minnawi said his troops were waiting to see whether the Janjaweed were serious about implementing the peace agreement. "We certainly won't disarm until we see them do so," he said.

Pronk said that getting the smaller rebel groups on board was crucial because there had recently been increased cases of infighting among rebels.

He said he was not in favor of immediately inflicting sanctions on field commanders still fighting, because that had not yet all been informed of the peace agreement. "But people who are impeding the peace process could be sanctioned," in accordance with U.N. Security Council resolution 1591, he said, describing as "cowards" the commanders who refuse to comply with the peace agreements and continue to kill civilians.

"There has been further deterioration of the human rights situation since February," he said.

"That peace has been signed in Abuja doesn't mean everything is fine or that there will immediately be peace on the ground," he said.