Tensions between all Darfur's ethnic groups have worsened in the last decade
At least 63 people have died in clashes between rival Arab groups in Sudan's arid Darfur region, witnesses say.
One Sudanese radio station said its sources reported that more than 300 had died in the fighting between the Rezeigat and Maaliya.
The two nomadic communities have clashed before, usually over land and grazing rights in East Darfur.
More than a decade of unrest in the Darfur has spawned lawlessness and increased inter-ethnic rivalry.
Many people who have fled their homes in the last decade live in refugee camps
Rebels from non-Arab groups first rose up in 2003, accusing the government of favouring Arab communities.
In recent years, the biggest contributor to the death toll has been violence between different Arab groups.
According to Sudan's Radio Dabanga, the dispute in East Darfur began over the theft of a camel, a horse and two donkeys.
A source told the AFP news agency that heavy weapons were used in the fighting.
Representatives from both sides have appealed for the authorities to help resolve the dispute.
Since the civil war began in Darfur, the UN estimates that more than two million people have fled their homes.
Many stay in camps which are patrolled by a joint UN-African Union force that has more than 17,000 armed personnel on the ground in Darfur.