A UN official in South Sudan has spoken of an atmosphere of fear and desperation as violence continues in South Sudan.
Humanitarian Co-ordinator, Toby Lanzer, spoke about summary executions in Bor, in the restive state of Jonglei that has fallen to rebels.
He told the BBC he had witnessed “some of the most horrible things that one can imagine”.
“People were being lined up and executed in a summary fashion. This is done by people who are simply out of control,” Mr Lanzer said.
The UN mission in South Sudan has urged rival political leaders to agree a truce and open negotiations.
Meanwhile, the US said it had evacuated its citizens from Bor. Although its evacuation operation was initially aborted due to shots fired at its military aircraft, the US re-entered the region using civilian US and UN helicopters.
Clashes broke out between troops loyal to President Salva Kiir and others backing his former deputy, Riek Machar on Sunday night after President Kiir claimed to have quashed a coup attempt on his government by soldiers loyal to his former deputy.
Sudan suffered a 22-year civil war that left more than one million people dead before the South became independent in 2011.