The army of south Sudan says 82 people have been killed in fighting between rebel militia and civilians in Warrap state.
Army spokesman Philip Aguer said Tuesday that the clashes broke out when rebels attacked a cattle camp, killing 34 people and wounding 45.
He says the cattle herders later ambushed the militiamen, killing 48 of them.
Aguer said the rebels entered Warrap after troops chased them out of neighboring Unity state last week.
Unrest in south Sudan has raised concerns about the region's stability as the south prepares for independence from the north on July 9.