Dozens of government troops have been killed during a rebel ambush in Sudan's Darfur, a regional analyst said on Thursday, confirming an unusually high toll for the troubled region.

There were "huge" casualties on the government side, numbering in the "dozens", although exact figures were unclear, the analyst told AFP on condition of anonymity.

Rebels were also killed, though in lesser numbers, he added.

The Minni Minnawi faction of the Sudan Liberation Army, and the Sudanese military, both said a clash occurred last Sunday about 50 kilometres (30 miles) southwest of El Fasher, the capital of North Darfur state.

"We killed 200 regime troops," said Abdullah Moursal, spokesman for the Minnawi faction.

He also said rebels seized about two dozen vehicles from government forces in the battle a few kilometres outside Tabit town.

"Yes, they tried to ambush a SAF convoy but we defeated them, and the convoy continued on its journey," said Sawarmi Khaled Saad, the Sudan Armed Forces spokesman.

He said he had no details on casualties.

Death tolls in the dozens, or even higher, are more common during Darfur's inter-ethnic militia fighting rather than government-rebel clashes.

The inter-ethnic tribal fighting, mostly involving Arab groups, has been the main cause of an upsurge of violence in Sudan's far-west Darfur region this year.

The Sudan Liberation Army and other non-Arab rebels have been battling the government for 10 years in Darfur.

The conflict was sparked by what they considered domination of Sudan's power and wealth by Arab elites.

In the latest tribal fighting, more than 20 people died on October 27 when the Misseriya and Salamat tribes clashed near Mukjar town in Central Darfur, the UN's Office for the Coordination of Humanitarian Affairs (OCHA) said Thursday in its latest weekly bulletin.

The Salamat and Misseriya have been fighting on-and-off for months, with more than 170 people killed, according to reports received by the United Nations.

Two peace agreements during that time have failed to halt the tit-for-tat violence.

"Fighting between the Salamat and Misseriya tribes continues to be a major security concern in the localities of Umm Dukhun, Mukjar and Bindisi in Central Darfur," OCHA said in its bulletin.

The cash-starved Sudanese government can no longer control its former Arab tribal allies, and violent competition for resources has intensified, analysts say.