An attack on a United Nations compound in South Sudan which left three Indian peacekeepers dead on Thursday has deepened confusion there.
It followed what is said to have been a failed coup on Sunday, with hundreds of deaths after fighting between the army and dissidents.
UN Deputy Secretary General Jan Eliasson said: “I’ll tell you how deeply concerned the Secretary General and I and our colleagues are about the current situation in South Sudan. Our base in Akobo, Jonglei State, was attacked and we have reports that lives are lost.”
The authorities in Juba say the violence was started by rebels affiliated with Riek Machar. Officials say he has fled the scene of a massacre in Bor, capital of the major northeastern state of Jonglei in South Sudan.
Members of the Dinka clan of President Salva Kiir Mayardit are accused of killing soldiers of another clan, the Nuer.
The organisation Human Rights Watch says selective murders are being carried out according to ethnicity, and against those loyal to the president.
Salva Kiir on Wednesday said he was ready to parlay with his former vice president, Machar, but the latter said he would only talk if Kiir stepped down.
Washington has sent four dozen of its soldiers to protect American nationals in the trouble zone. US president Barack Obama has said South Sudan is on the brink of civil war. In July 2011, Obama supported the partition of Sudan, and the creation of the South as a new country.