South Sudan Says Recaptures Oil-Producing State From Rebels

U.S. Weighs Sanctions

Separately, sources briefed on U.S. discussions said Washington was weighing targeted sanctions against South Sudan due to its leaders' failure to end the crisis. Such sanctions focus on individuals, entities or sectors in a country.

"It is a tool that has been discussed," one source told Reuters, on condition of anonymity.

The possibility of sanctions against a country Washington helped create in 2011 shows how frustrated President Barack Obama's administration has become with Kiir and Machar's rebel faction.

Washington on Thursday also cranked up the pressure for a deal, saying South Sudan risked losing hundreds of millions of dollars in U.S. aid if the two sides did not end the violence.

The fighting, often along ethnic lines, is the worst in South Sudan since it won independence from Sudan in 2011. The unrest threatens to destabilise fragile east Africa.

U.N. Secretary-General Ban Ki-moon urged Kiir to release all political detainees and called for "the two sides to negotiate in earnest."

And earlier on Friday, the United Nations in South Sudan accused both rebels and government forces of obstructing aid.