Direct talks on South Sudan open in Ethiopia
Direct talks on ending the conflict in South Sudan have officially opened in the Ethiopian capital, Addis Ababa.
The negotiations are focusing on bringing about a ceasefire and the release of political prisoners.
The talks, led by teams representing the warring parties, are expected to get under way in earnest on Sunday.
Rebels supporting sacked Deputy President Riek Machar are involved in fierce fighting with the forces of President Salva Kiir.
At least 1,000 people have been killed since the conflict began on 15 December.
More than 180,000 people have been displaced.
Earlier fears that the talks in Ethiopia had been postponed indefinitely proved unfounded with the unexpected ceremonial opening at a hotel in Addis Ababa.
In a tweet on Saturday evening, the Ethiopian foreign ministry quoted the special envoy to South Sudan as saying "both the government & opposition of South Sudan have committed to resolve their political differences through political dialogue".
No timeline has been set, but mediators have asked the opposing parties to find quick solutions.
The BBC's Alastair Leithead in the South Sudan capital, Juba, says both sides think they have the upper hand and, with their positions so far apart, something dramatic must change for a speedy agreement.
Obstacles to talks
South Sudan's Foreign Minister Barnaba Marial Benjamin told the BBC that the rebels would have to acknowledge that they had instigated a coup attempt. He said the government's compromise was to have agreed to the talks.
US Secretary of State John Kerry said on Sunday that the talks must not be "a delay gimmick in order to continue the fighting and try to find advantage on the ground at the expense of the people of South Sudan".
He added: "We will work to apply international pressure to any elements that attempt to use force to seize power. That is not acceptable."
Nhial Deng Nhial, head of the government negotiating team, pledged to "leave no stone unturned in the search for a peaceful resolution", according to AFP news agency.
But he warned it "must be abundantly clear" the government has "an obligation to restore peace and security of the country through all means available".
Rebel delegation chief Taban Deng told AFP he was committed to talks, but demanded the release of several top political leaders from the ruling Sudan People's Liberation Movement (SPLM), accused of involvement in the violence.
Mr Machar, in an interview with the UK's Daily Telegraph newspaper, said his forces would hold back from attacking Juba to try to reach a negotiated settlement.
"I'm being restrained by the international community and the talks, which I hope will yield some fruits," he said.
But the sounds of firing were reported from Juba on Saturday evening.
And earlier reports spoke of heavy fighting on the outskirts of the rebel-held city of Bor, in Jonglei state.
South Sudan is the world's newest state. It was formed in 2011, gaining independence from Sudan after decades of conflict.
The latest trouble has its roots in tensions that go back long before 2011.
Politicians' political bases are often ethnic. President Kiir is from the Dinka community while Mr Machar is a Nuer.