Thousands of civilians in Sudan's troubled Darfur region have sought protection around peacekeeping bases after rebel attacks and "possible" air strikes, the mission said on Sunday.

The African Union-United Nations Mission in Darfur (UNAMID) confirmed rebels of the Sudan Liberation Army's Minni Minnawi faction "attacked and seized" the towns of Muhagiriya and Labado.

On Saturday the rebels said they had killed government troops and occupied the areas, about 100 kilometres (60 miles) east of the South Darfur state capital Nyala.

"At both locations, UNAMID personnel reported several possible air strikes and are taking steps to ascertain the number of casualties caused by the fighting," the peacekeepers said in a statement.

"Thousands of civilians, many with their livestock, are concentrated around UNAMID team sites in Muhagiriya and Labado for protection. The pressure from the presence of civilians, especially in Muhagiriya, is growing."

The latest unrest came as insurgents, who have been fighting for 10 years in Darfur, denounced an international donor conference which seeks support for "rebuilding" the devastated region.

"I would like to condemn very strongly" the meeting which began Sunday in the Gulf state of Qatar, said Abdel Wahid Mohammed al-Nur, who heads another faction of the Sudan Liberation Army (SLA).

"To have (a) donors' conference you have to have peace and security on the ground first," said Nur, who launched the uprising in 2003.

Speaking to AFP, he alleged that donated money "will not go to the people".

Gibril Adam Bilal, spokesman for the Justice and Equality Movement (JEM), asked the international community "not to participate in giving the government of Sudan a chance to conduct crimes" against the people.

The Doha conference, which ends on Monday, was agreed under a July 2011 peace deal which Khartoum signed in the Qatari capital with an alliance of rebel splinter groups.

Major rebel movements including JEM and the SLA have refused to sign the peace pact, although a breakaway faction of JEM acceded to the deal on the eve of the donors' conference.

While the worst of the violence has long passed, rebel-government clashes continue along with inter-Arab battles, kidnappings, carjackings and other crimes.

But the $7-billion draft development strategy on the table in Doha says there will probably never be an ideal time for recovery, and delays can only make the process more difficult.

Sudan is perceived as one of the world's most corrupt countries. The development plan proposes an independent monitoring mechanism and says other safeguards will be built in, including from the UN and World Bank.

President Omar al-Bashir is wanted by the International Criminal Court for war crimes, crimes against humanity and genocide allegedly committed in Darfur.

His defence minister and a state governor are also wanted.