More than 300 people were killed and thousands sent fleeing into bush during two weeks of fighting between South Sudan's army, rebels and rival tribes in the east of the country last month, officials said on Thursday.
South Sudan's army is grappling with a rebellion led by politician David Yau Yau in vast Jonglei state and new clashes have broken out between the Lou Nuer and Murle tribes. More than 1,600 people have been killed in a cycle of tribal violence in Jonglei since the break-up of Africa's largest country.
Western powers are worried the violence will escalate into full-blown civil war, undermining stability in the young African country, which is awash with arms after decades of conflict with Khartoum that led to its secession from Sudan in 2011.
A team of local chiefs travelling around Pibor County in Jonglei had reported 328 deaths so far - all Murle members and some of them women and children, according to Jodi Jonglei Boyoris, a senior state representative. The number of Lou Nuer killed and wounded remained unknown.
Boyoris said he expected the death toll to rise although the fighting had died down this month.
Representatives of the South Sudan army and humanitarian groups said they were not able to confirm the figures.
Boyoris said the fighting ended nearly three weeks ago but local officials were only now able to count the number of killed and wounded as people had started returning to their homes.
The United Nations has said thousands of people are hiding in the bush outside Pibor town in Jonglei to avoid the conflict between the army and Yau Yau, who says he is fighting corruption, army abuses and one-party rule in South Sudan.
The United Nations estimates 100,000 people have been affected by the conflict, with many fleeing to the bush and cut off from humanitarian access.