Khartoum - The international peacekeeping mission in Sudan's Darfur is "gravely concerned" by tribal fighting in the region, a spokesperson said on Monday, as efforts began to halt the latest clashes.
Sources in the Taisha and Salamat Arab tribes told AFP late on Sunday that tribal militias used rockets, artillery and heavy machine-guns in battle across a wide swathe of southwest Darfur.
"Unamid is gravely concerned about the escalation of inter-tribal fighting," Ashraf Eissa of the African Union-UN Mission in Darfur said, after the mission received reports of violence among Misseriya, Taisha and Salamat tribes in parts of Central Darfur state in recent days.
"The number of casualties has not been confirmed," Eissa said.
Worsening tribal militia violence has already killed hundreds in Darfur this year.
The Salamat have been fighting off-and-on with the Misseriya, a Taisha ally, in southwest Darfur since April.
Two peace agreements during that time have failed to halt the tit-for-tat attacks.
On Monday, a committee of tribal leaders and administrators met in an attempt to negotiate a peaceful end to the latest conflict, Eissa said.
The Taisha and Salamat said Sunday's battle was sparked by a land dispute.
Tribal sources could not be reached on Monday.
Analysts say cash-starved Khartoum can no longer control its former Arab tribal allies, whom it had earlier armed against a rebellion in the region, and competition for resources has intensified.