However, the government-linked Sudan Media Centre quoted Brigadier-General Osman Mohamed al-Aghbash, an army spokesman, as saying that troops had inflicted heavy casualties on the rebels as they fought off the attack.

Saiki said that hundreds of civilians had sought refugee with peacekeepers during the fighting.

"We presume that it's the Jem [Justice and Equality Movement] because of recent clashes in this sector," he said.

Kornoi seized

Umm Baru has seen a number of clashes between pro-government forces and Jem fighters over the past two weeks.

In depth

 
 Who are Sudan's Jem rebels?
 Video: Darfur rebels fight to forge new country
 Video: Chad camps foster Darfur rebels
 Timeline: Darfur crisis

The group's fighters recently seized control of the nearby town of Kornoi and captured several Sudanese soldiers there.

Suleiman Sandal, a Jem commander, told the Reuters news agency earlier on Sunday said that Sudanese government aircraft had been bombing around Kornoi and Umm Baru every day since his fighters took the town.

Air attacks in Darfur are banned under UN security council resolutions and a series of failed ceasefires, but Khartoum has in the past reserved the right to attack Jem and other rebel groups that did not sign a peace deal in 2006.

The latest round of peace talks between the Khartoum government and Jem leaders are due to begin in Doha, the capital of the Gulf state of Qatar, on Wednesday.

Ahmed Ben Abdallah Al Mohmoud, Qatar's foreign minister, held talks with Omar al-Bashir, Sudan's president, on Sunday to discuss the situation.

Chad tensions

Sudanese state media said Al Mohmoud was also planning to visit Chad in a bid "to solve the problems between the two countries".

Tensions along the border between the pair have been mounting for several weeks as each accuses the other of supporting rebel groups seeking to topple their respective governments.

Ndjamena has accused Khartoum of backing a recent offensive by Chadian rebels, while Sudan has said that Chad backs the Jem rebels.

Darfuri rebel groups took up arms against government soldiers and allied militias six years ago and up to 300,000 people are thought to have died in the ensuing violence, according to the UN.