Warring parties in Sudan's Darfur region have been given another 48 hours to reach agreement on a peace deal.
African Union (AU) mediators agreed the extension after a deadline at talks in the Nigerian capital, Abuja, passed without a deal.
The Sudanese government has agreed to sign the AU-backed agreement, but the rebels have no common position.
Two of the rebel factions have rejected the deal as it stands, but the main SLA group has not ruled out an agreement.
"We have to stop the clock for the next 48 hours to allow the parties to hold more talks," the AU's chief negotiator, Salim Ahmed Salim, said at a late-night meeting of negotiators from both sides.
"If we walk away from here, without a peace deal, the world will not forgive us," he said. "I urge the parties to reflect in the next 48 hours on how to breach the existing gap."
The extension, until midnight on Tuesday, came after a request from US officials for more time for the parties to resolve outstanding issues.
The peace plan in question calls for pro-government Arab militias to be disarmed, and rebels fighters to be merged into Sudan's forces.
The 85-page draft also aims to end what Darfur rebels say is long-standing neglect of the province by the Khartoum government.
It calls for a one-off transfer of $300m to Darfur, with $200m a year for the region thereafter.
The Khartoum government announced its acceptance of the peace plan on Sunday.
The rebel groups have held a series of meetings to work out a common position.
Concern over the demand for rebel forces to lay down their arms before they are integrated into the Sudanese army appeared to be one sticking point.
Some rebel leaders are also reportedly demanding the Sudanese vice-presidency.
The small Justice and Equality Movement (Jem) and one faction of the main group, the Sudan Liberation Army (SLA), refused to sign the deal as the midnight deadline passed.
Jem spokesman Ahmed Hussein told the BBC the peace plan failed to address his group's "minimum demands" and favoured the Khartoum government.
However the chief negotiator of the SLA left the possibility open that a deal could be reached. The BBC's Alex Last says that if the SLA mainstream can be brought on board, others are likely to follow.
As the talks continued, campaigners held a series of mass rallies across the United States calling for an end to the conflict.
Speakers in Washington included the actor George Clooney, who described Darfur as "the first genocide of the twenty-first century".
"We're at the doorstep of something we thought was impossible to dream of in the twenty-first century," he said.
"If we turn our heads and look away and hope that it'll all disappear, then it will. All of them, an entire generation of people."
The United Nations' top human rights official, Louise Arbour, meanwhile, began a six-day visit to Sudan, with a visit to Darfur first on the schedule.
The AU - which has 7,000 peacekeepers in Darfur - has struggled to stop the violence between the rebels and the government-backed Janjaweed militias.
The conflict began in early 2003, when rebel groups began attacking government targets.
It has killed 200,000 people and driven more than two million from their homes.