Khartoum - The US envoy for Sudan, Scott Gration, is due to meet Darfur rebel leaders in neighbouring Chad in a bid to revive the stalled peace process.

Mr Gration is hoping to talk to officials from two rebel groups - the SLA and Jem - as well as Chad's President Idriss Deby. Chad and Sudan accuse each other of backing rebel groups which operate across their troubled border.

Some 300,000 people have died in the six-year conflict, the UN says.

The BBC's Celeste Hicks in N'Djamena says it is an open secret that leaders from the Justice and Equality Movement (Jem) are often in Chad's capital.

Many are from the same Zaghawa ethnic group as President Deby. Leaders of Abdul Wahid's faction of the Sudan Liberation Army (SLA) are also in Chad for the talks.

Diplomatic sources say that the US envoy is hoping for a sign of the rebels' willingness to agree to a cessation of hostilities and to become more of a political force.

However just four weeks ago Jem said they took and briefly held the towns of Kornoi and Um Baru in Darfur, and Jem sources told the BBC that they may consider trying to retake Kornoi if the circumstances are right.

Although Mr Gration initially said it was not in his mandate to talk to Chadian rebels who recently staged an attack in the east of Chad, it is thought that he may now try to look at their role in the whole destabilisation of the region.

Chad accuses Sudan of backing these rebel groups.

Recent peace talks have stalled, partly because the rebels have split into so many different groups.