Mediators, rebels and the government have asked African Union (AU) chairman and Nigerian President Olusegun Obasanjo to intervene and try to break the stalemate.

"We are waiting for him to come back and take a decision on the matter," AU spokesman Assane Ba said on Friday of Olusegun, who is on his way back from an AU summit in Burkina Faso. 

The rebels insist on an immediate disarmament of the pro-government Janjawid militia, a no-fly zone over Darfur, an independent international human rights committee, and an increased AU troop presence on the ground.

The government rejects these demands and says the rebels must start withdrawing their troops into containment areas. Rebels said no deal was likely, as a result. 

Rejecting accusations

Earlier on Friday, Khartoum rejected US accusations that it carried out "genocide" in its troubled western Darfur region, scene of what the United Nations calls the worst humanitarian catastrophe in the world today. 

US Secretary of State Powell said
'genocide' was going on in Darfur

Sudanese officials dismissed the US declarations as an election ploy by the Bush administration and warned that they comments could prolong the conflict that has already claimed tens of thousands of lives. 

"We strongly believe the Bush administration is trying to distract internal and international attention away from what is taking place in Iraq to avoid pressure from the Democrats during the ongoing presidential election," Foreign Minister Mustafa Usman Ismail told reporters during a visit to South Korea. 

"They should not use our humanitarian crisis for their own political agenda," he said. 

Khartoum's ambassador to Washington also categorically rejected US Secretary of State Colin Powell's description of atrocities in Darfur. 

"To consider what is happening in Darfur as genocide does not represent the international consensus and sends a negative signal to the other side who are negotiating with the government," Khidir Harun was quoted as saying in a letter published by the Sudanese press. 

Appalled

Powell told a Senate hearing that evidence compiled by the US "concluded that genocide has been committed in Darfur and the government of Sudan and the Janjawid bear responsibility, and that genocide may still be occurring". 

"They should not use our humanitarian crisis for their own political agenda" 

Mustafa Usman Ismail,
Sudan foreign minister

Bush said he was "appalled" by the violence and called for the UN to undertake a full investigation of the "genocide and other crimes in Darfur". 

He said his government was seeking a new Security Council resolution to authorise an expanded AU security force to prevent further bloodshed and would seek to ban flights by Sudanese military aircraft over Darfur. 

But the 15-nation Council has emerged divided over the proposed US resolution which hangs the threat of sanctions over Sudan, with Russia, Pakistan and especially China voicing strong objections to the draft. 

The resolution, like a similar measure passed on 30 July, demands that Khartoum should disarm and rein in the Janjawid and take other steps to end the violence or face international sanctions.