The African Union has extended the deadline for peace talks over the Darfur region of Sudan as Western countries try to push the factions toward an agreement to end the violence.

The U.S. representative at the talks, deputy undersecretary of state Robert Zoellick, emerged from the negotiations on Tuesday to announce that the negotiations will continue for at least another day.

"I will be here tomorrow [Wednesday], beyond that I don't know," he told reporters.

Originally, there was a Sunday deadline for the talks, but the rebels rejected a draft peace accord which the Sudanese government had accepted.

Two militant groups, the Justice and Equality Movement and the SLM, rejected Sunday's deal, saying it didn't meet their needs for more autonomy for Darfur and better representation in the Sudanese government.

The AU, which has been running the talks for two years, then extended the deadline for 48 hours, until midnight Tuesday, local time.

One of the rebel negotiators, Calfaddin Aroun of the Sudanese Liberation Movement, said earlier that he was not optimistic. "There's no solution yet," he said. "We're waiting to go home."

Fighting has killed 180,000

The militant groups, mostly non-Arab tribes, began fighting in 2003 against the Arab-dominated government. The government has been accused of backing the Arab militias, known as the Janjaweed, which have been fighting the militants and are accused of rapes, murders and genocide.

The AU, United Nations and West all are pushing for an end to the fighting which has killed 180,000 people and displaced two million.

U.S. President George W. Bush called Sudanese President Omar al-Bashir on Monday night, but Sudan has said that it agreed to the Sunday proposal, and it's up to the militants to accept a deal.

Canada's UN ambassador, Allan Rock, is also in Nigeria where the talks are being held.

Mediators have complained that the parties are not willing to compromise.