South Sudan's warring parties have arrived in Addis Ababa for talks aimed at ending nearly three weeks of conflict that has left thousands dead, as fighting continued in the world's newest nation.
Government and rebel negotiating teams had both arrived in the Ethiopian capital by Wednesday evening, a source close to the talks told AFP.
United Nations special envoy Hilde Johnson said in South Sudan's capital Juba it was "positive that they are sending delegations", underscoring the dire need for "reconciliation and healing" after the violence that has forced 200,000 people to flee their homes.
"Negotiations also need to be accompanied by something else, a deeper process that focuses on national reconciliation between the communities. We have seen terrible acts of violence in the past two weeks ... and as we know, if there is no one held accountable, there is a major risk that the violence can continue," she said.
Ethiopia, which is brokering the talks, said they would focus on monitoring mechanisms for a ceasefire. The sides will begin talks on Thursday, but formal negotiations may not open for several days, the country's foreign minister said.
Fighting broke out in South Sudan on 15 December last year, when President Salva Kiir accused former deputy Riek Machar of attempting a coup.
Mr Machar has denied this, in turn accusing Mr Kiir of conducting a violent purge of his opponents, and the fighting has spread across the country, with the rebels seizing several areas in the oil-rich north.
On Tuesday, they recaptured Bor, the capital of Jonglei state and situated just 200km north of the capital. The government confirmed on Wednesday it had lost control of the strategic town, which has changed hands three times in the past two weeks, as fighting reportedly continued in the area.
Thousands of people are feared dead, UN officials say, while hundreds of thousands of civilians have been forced to flee their homes - many seeking refuge with badly overstretched UN peacekeepers.
Riek Machar told AFP on Tuesday that he was not yet ready to agree to an immediate ceasefire nor hold face-to-face talks with the president, and that his forces were marching on Juba.
"There is no cessation of hostilities yet. That is what the delegation going to Addis Ababa is going to discuss and to negotiate. I will follow later, once the negotiations have resulted in a cessation of hostilities. It depends on if and when that is achieved."
Mr Kiir has described the war as "senseless", but has ruled out power sharing with the rebels. He has also rejected their demands that a number of their loyalists, arrested shortly after the violence started, be freed.
"What power sharing? It is not an option. This man has rebelled. If you want power, you don't rebel so that you are awarded with the power," he said in an interview broadcast on the BBC.