Mediators halted the talks 10 minutes after they resumed on Tuesday after hearing from the warring parties that there had been no change in their positions since Friday's breakdown in dialogue.
The talks were adjourned on Friday after the Sudanese government rejected an AU plan to restore security in the western region of Darfur, where a 19-month conflict has claimed an estimated 50,000 lives and forced 1.4 million from their homes.
Nigerian President Olesegun Obasanjo, the current AU head, later met government and rebel delegates for two hours, but failed to extract a compromise on disarmament and security – the key issues which have bogged down the talks for several days.
The Darfur conflict has killed
50,000 and displaced 1.4 million
"I can't say the deadlock is broken. We met with President Obasanjo and we stated very clearly our position," the chief negotiator of rebel Justice and Equality Movement, Ahmad Muhammad Tugod said.
Sudan's deputy foreign minister Najib Abd Al-Wahab blamed the United States for the deadlock.
Last week US Secretary of State Colin Powell said Sudan's government was guilty of 'genocide'.
"The negotiations have been very much undermined by Mr Powell's declaration which led the rebels to stay very firmly on their positions," the deputy minister said.
"The United States needs to inject new blood into these negotiations by sending the right signals to our brothers who are using this statement not to move forward in the talks".
“The negotiations have been very much undermined by Mr Powell’s declaration which led the rebels to stay very firmly on their positions”
Najib Abd Al-Wahab
Sudan's deputy foreign minister
The United States, meanwhile, has put forward a new draft UN resolution threatening sanctions on Sudan's oil industry if the government does not end the bloodshed in Darfur.
The new draft presented on Tuesday said the threat of sanctions – opposed by several Security Council members earlier – would be "considered" if Sudan did not comply.
The resolution also calls for beefing up a force from the AU already on the ground to monitor a fragile ceasefire between Sudan and the rebels.
"Our hope is that the vote will come towards the end of this week," said US ambassador John Danforth.