"We are studying the situation closely. We have contacted the mediators. We will see what takes place in the coming hours," Adam said.

He said Sudanese forces were advancing in the east Jabel Marra area of central Darfur.

Amin Hassan Omar, the Sudanese culture minister, acknowledged that "hostilities" were still taking place.

"As long as there is no agreement between the two parties, there cannot be an order to the armed forces to stop the fighting," he said.

Omar described the peace talks as "preparatory, no more, no less".

Rebel proposals

Taher al-Fakki, a Jem politician, told Al Jazeera that the Khartoum government will have to put a number of proposals on the table.

At regional level, the government should "compensate Darfurians, guarantee easy return of refugees and expel those who occupied their land.

"At the national level, the government should agree on power sharing and security arrangements" as key issues, al-Fakki said.

"We need cessation of hostility urgently ... to solve the problem of Darfur"

Djibril Bassole, UN mediator

Djibril Bassole, the UN and African Union mediator for the Darfur crisis, told Al Jazeera: ''We need cessation of hostility urgently. I think if the Doha meeting could provide cessation of hostility in Darfur, or at least suspension of hostility, then we could move forward to solve the problem."

Jem boycotted a peace deal signed by one other faction in 2006 and launched a series of attacks on Khartoum, the Sudanese capital, from May last year.

Sheikh Hamad bin Jassim al-Thani, the Qatari prime minister, told the talks' opening session on Tuesday that he hoped that "other Darfur rebel groups would join the negotiations".

But several rebel groups have said the peace effort would fail because it did not include all factions.

Minni Arcua Minnawi, the only rebel to sign a failed peace deal with the Khartoum government in 2006, said the Doha talks would be "a major disaster".

"If the Abuja agreement was lacking then what is happening in Qatar is lacking even further," he said.

Separately, Suleiman Jamous, a senior member of the Sudan Liberation Army's Unity faction, said that Khartoum and the mediators have mistakenly concluded that Jem is the biggest rebel group in Darfur.