Sudanese rebels have refused to sign a draft peace accord aimed at ending the violence in Sudan's western Darfur region.
A spokesman for the rebel Justice and Equality Movement (JEM) said there must be changes to the agreement before the group will sign it.
The rebels said they wanted better terms for integrating their forces into the Sudanese army, and for disarming pro-government Janjaweed militias.
Sudan's government had said it was ready to accept the deal.
Midnight Sunday was the African Union's deadline for a peace settlement.
U.S. and U.N. officials supported the peace agreement.
Three years of violence in Darfur between government-backed forces and Darfur rebels have left tens of thousands of people dead and more than two million displaced.