At least 58 people have been killed in clashes between tribes over cattle in South Sudan.
Ethnic groups in South Sudan have fought each other over cattle, a vital part of the indigenous economy for centuries.
But the numbers of deaths are increasing after decades of civil war left the territory awash with small arms.
Analysts say South Sudan, which became independent on 9 July, risks becoming a failed state if it cannot control insurgencies and blood feuds that divide its tribes.
A United Nations spokesman has said that violence between the Murle and Lou Nuer tribes broke out on Thursday.
From the beginning of the year up to the end of June, 2,368 people have been killed in 330 violent incidents across the South, according to UN data released in July.
South Sudan's government has accused the north of arming rival tribes and provoking insurgencies to try to undermine the region and keep control of its oil. Khartoum denies the charge.
