Juba-South Sudanese army revealed that two rival tribes are fighting in the restive Jonglei state.
The Spokesman of South Sudan army, Col. Philip Aguer, said Thursday ethnic clashes had erupted between the rival Lou Nuer and Murle tribes in Pibor County, the scene also of a South Sudanese military assault against militia led by a renegade colonel named David Yau Yau.
Aguer said South Sudan's army had not received orders to intervene in the ethnic clashes.
The U.S. Embassy in South Sudan in a statement Wednesday urged community leaders to "call on all armed youth to lay down their weapons immediately."