Sudan's government and rebels from Darfur opened talks late Sunday, as mediators pushed for a ceasefire to end over a decade of war and insurgents warned the country was close to "collapse".
African Union chief mediator Thabo Mbeki called for a cessation of hostilities between the government and two rebel factions, part of wider efforts to stem multiple rebellions across Sudan.
Previous years of talks have made little if any change to the conflict in the arid, western region that the UN says has killed 300,000 and forced two million from their homes.
"There can't be anyone in Sudan who would benefit from these conflicts," said Mbeki, a former South African president, speaking at AU headquarters in Ethiopia.
"It is important that everything should be done to end all the violent conflicts around the country... so as to facilitate national dialogue," Mbeki added.
Rebels, who took up arms in 2003, accuse Khartoum's Arab-dominated government of marginalisation.
Government delegation leader Amin Hassan Omer stressed Khartoum's "faithful committment... to reach an agreement on a ceasefire."
But rebel chiefs were sceptical the government wants peace.
Minni Minnawi, who coordinates the rebel Sudan Revolutionary Front (SRF) coalition, accused Khartoum of "atrocities at the level of genocide" and said Sudan is "on the verge of collapse."
Rebel chief Mohamed Gebreil, of the Justice and Equality Movement (JEM), said he was doubtful the government really wanted to end the war.
"Though there are many elements to the conflict in Darfur, the heart of the solution is relatively simple - government support for a legitimate peace process," Gebreil said.
"Even now, the government continues to define the problems in Darfur through a purely military lens and pursue only military options to address issues," he added.
President Omar al-Bashir is wanted by the International Criminal Court (ICC) for alleged war crimes committed in Darfur, and Minnawi demanded he face trial.
"Delayed justice is denied justice," Minnawi added. "We therefore call on the ICC to step up its efforts to bring the criminals who committed crimes before justice."
Earlier this month Sudan's government met with rebels from South Kordofan and Blue Nile, part of the SRF coalition. Mediators said the week of talks were "positive" but no deal was struck.
Fighting there erupted shortly before South Sudan split from Sudan in 2011.