Officials in southern Sudan say tribal clashes over livestock have left 21 people dead.

A spokesman for the south Sudan army, Kuol Deim Kuol, said the fighting took place Monday when cattle raiders attempted to steal hundreds of cattle from a camp in Yirol East.

He said one person from the raided community was killed while 20 of the attackers died.

Kuol said the raid and deaths were a criminal issue, and not a mark of deeper tensions.

The United Nations says more than 400 people have been killed and 60,000 displaced in tribal conflicts this year in southern Sudan.

Many of the clashes involve access to water, a sensitive issue to Sudanese whose livelihoods depend on raising cattle.  

Semi-autonomous southern Sudan is struggling to recover from more than two decades of civil war with the north that ended in 2005.

The region is scheduled to hold a referendum on independence next year as part of a peace deal with the north.

Some information for this report was provided by AP and Reuters.