Tribal fighting this month between rival Arab groups in Sudan's East Darfur killed 190 people, the United Nations said on Friday.

According to reports received by the UN, "100 Reizegat tribesmen were killed and another 140 were injured, while on the Maaliya side 70 were reportedly killed and 113 were injured" at one location, the UN's weekly Humanitarian Bulletin said.

During the fighting a Rezeigat source had told AFP that his side killed 70 Maaliya while 30 of his own men were killed.

In its bulletin, the UN's Office for the Coordination of Humanitarian Affairs (OCHA) said another 20 Rezeigat were reportedly killed and 45 injured in clashes at a separate location, where an unidentified number of Maaliya were killed.

On Thursday night the Rezeigat and Maaliya signed a document for "peace, co-existence and cessation of hostilities," the official SUNA news agency reported.

"Aid operations in East Darfur have been severely curtailed as a result of the fighting and general insecurity," OCHA said in its bulletin covering the period to August 18.

Non-Arabs in Darfur rose up 10 years ago against what they saw as the domination of Sudan's power and wealth by Arab elites.

In response, government-backed Janjaweed militias shocked the world with atrocities against them.

Although the rebellion continues, analysts say Sudan's crisis-hit regime now has less money for its militias, who are acting outside government control and have been a major contributor to violence in the region this year.

Tribal disputes have been driven by conflicts over resources, including land, water and mineral rights.