TAlks between South Sudan’s government and rebels are due to start later on Tuesday in Ethiopia, mediators say.
The two sides are expected to reach an agreement on the cessation of hostilities, they said.
The talks are the first since conflict erupted two weeks ago between forces loyal to President Salva Kiir and his sacked deputy, Riek Machar.
At least 1,000 people have died and more than 121,600 are believed to have fled their homes.
East African leaders have been leading mediation efforts to end the crisis.
On Monday, Uganda’s President Yoweri Museveni threatened the rebels with military action if they failed to agree to a ceasefire by the end of Tuesday, and begin talks.
Representatives of Mr Kiir and Mr Machar would meet in the Ethiopian capital, Addis Ababa, to defuse tensions in South Sudan, the Ethiopian government said in a statement.
“The two sides are expected to reach an agreement on the cessation of hostilities and peaceful resolution of the current political crisis,” the statement added.
Earlier, Mr Machar told the BBC he would send a delegation to the talks, claiming his forces had captured the key town of Bor.
But while he had agreed to negotiate, he said he would not order his troops to stop fighting.
He had previously demanded 11 detainees accused of being co-conspirators in a coup plan be freed before negotiations.
Mr Machar, who was deputy president until he was sacked in July, denies there was a plot – alleged by Mr Kiir.
The fighting initially broke out in South Sudan’s capital, Juba, and has now spread to many parts of the country.
The situation in Bor is fast-moving, but a government minister confirmed that the town had fallen to Mr Machar’s forces, reports the the BBC’s James Copnall from Juba.
South Sudan President Salva Kiir told James Copnall a peaceful solution was still possible
A UN spokesman said Bor, the capital of Jonglei state, had come under attack at day break, not far from the town’s UN compound.
Mr Machar said his delegation to talks would be headed by Rebecca Nyandeng, the widow of John Garang, who led South Sudanese rebel forces against Khartoum for many years.
Our reporter says as a Dinka she may help Mr Machar challenge the allegation that his rebellion is primarily from his Nuer ethnic group.
Mr Machar’s forces are a mix of mutinous soldiers loyal to him and an ethnic militia called the “white army”, known for putting white ash onto their bodies as a kind of war-paint.
Observers say the talks are likely to be complicated, as the two sides will have to agree on a mechanism to monitor a ceasefire.
Mr Kiir has also ruled out any power-sharing arrangement with Mr Machar in the longer term.
South Sudan is the world’s newest state. It was formed in 2011, gaining independence from Sudan after decades of conflict.
