Clashes between two Arab tribes in Sudan's war-torn state of East Darfur have killed up to 10 people this weekend, tribal leaders told AFP news agency on Sunday.

The fighting that began on Saturday comes as the United Nations and African Union prepare to downsize their peacekeeping mission in Darfur, saying that overall violence there has diminished.

The clashes between the Arab Maaliya and Rizeigat tribes came months after a similar clash left at least nine dead.

The two tribes have a history of violence over land ownership rights and allegations of cattle theft.

"A group of tribesmen from Maaliya were ambushed by members of Rizeigat when they tried to chase thieves who had stolen livestock belonging to Maaliya tribesmen," said Ahmed Nour, a Maaliya leader.

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He said 10 people were killed and 18 wounded in the clashes on Saturday 40 kilometres southeast of El-Daien, the capital of East Darfur.

The chief of the Rizeigat tribe, Mohamed Madibu, told AFP that the two groups also clashed on Sunday.

He said that three Rizeigat were killed in the initial clashes on Saturday.

"A group of Maaliya attacked some Rizeigat villages yesterday. There are clashes even today, but we don't have details about casualties," Madibu said.

The UN and African Union peacekeeping mission in Darfur, known as UNAMID, said initial reports received by the mission put the death toll at nine, including six from Rizeigat tribe.

"The mission is verifying the exact number of casualties on both sides, while engaging with state authorities and community leaders to deescalate the situation," UNAMID said in a statement.

Khartoum limits international media access to Darfur so it was not possible to independently verify the toll, and Sudanese authorities could not be reached for comment.

Although Khartoum insists that the conflict in Darfur has ended, parts of the region have been destabilised by fighting between myriad ethnic and tribal groups.

The UN and the African Union maintain that the Darfur conflict is winding down, and their peacekeeping mission - among the costliest with a budget of more than $1bn - is being trimmed.

The Darfur conflict erupted in 2003 when ethnic minority rebels took up arms against President Omar al-Bashir's Arab-dominated government, accusing it of marginalising the region.

Since then, more than 2.5 million people have been displaced and 300,000 killed, the UN says.