KHARTOUM: Arab tribes fought with heavy machineguns and rocket-propelled grenades in Sudan's Darfur on Thursday, resuming clashes that earlier caused the largest displacement of the population in years, residents said.

About 100,000 people have fled or been severely affected since the Beni Hussein tribe and another Arab group, the Rezeigat, began fighting in the Jebel Amir gold mining area of North Darfur state in early January.

"Today at about 10:00 am the fighting started again when armed groups attacked two villages west of El Sireaf," said a resident of the town, where most of the displaced from the earlier fighting had fled.

"They were using Dushkas and RPGs and the fighting continued until sunset," the resident said, unable to provide a casualty figure.

A second person in El Sireaf confirmed the account.

The two tribes had reached an agreement to end the conflict, state-linked media reported in early February.

Eltigani Seisi, Darfur's top official, told AFP this week that Jebel Amir was "under the control of the armed forces" after the initial battles.

The United Nations had warned that aid delivery was in jeopardy for victims of the Jebel Amir violence unless authorities granted better access.

But on Thursday the UN's humanitarian agency, OCHA, said aid workers have since been better able to assess needs in the area.

"Relief supplies have now been delivered by road to all the locations affected by the Jebel Amir conflict, except Abu Gamra. Despite improved access, security remains a major concern," OCHA said in its weekly Humanitarian Bulletin.

Before the latest unrest, 1.4 million people were living in camps for people displaced by Darfur's decade-long conflict, the UN said.

A decade of civil war in Sudan's far-west region has been compounded by inter-Arab violence, banditry and tribal fighting.