ADDIS ABABA - South Sudan's warring parties opened negotiations in Addis Ababa Friday to strike a ceasefire deal and ending nearly three weeks of conflict, Ethiopia's foreign ministry said, although face-to-face talks are yet to begin.
"Negotiation started," the ministry said in a statement, adding that the regional East African bloc IGAD "was committed to support in any way possible".
The two sides are meeting with special envoys from regional nations, with sources suggesting the rivals may not meet directly until at least Saturday.
Government and rebel negotiating teams had begun arriving on Wednesday at a luxury hotel in Ethiopia's capital Addis Ababa, but the start of talks had been delayed until the full teams arrived.
"All members of the negotiating team from both the government and opposition of South Sudan (have) arrived," the ministry added.
Thousands of people are feared to have been killed in the fighting, pitting army units loyal to President Salva Kiir against a loose alliance of ethnic militia forces and mutinous army commanders nominally headed by ex-vice president Riek Machar.
Aid workers have increased warnings of a worsening crisis for civilians affected by the conflict, which some observers have warned risks deteriorating into full-blown civil war.
Fighting erupted on December 15 when Kiir accused Machar of attempting a coup in the world's newest nation.
Fighting has spread across the country, with the rebels seizing several areas in the oil-rich north.
Aid workers have increased warnings of a worsening crisis for civilians affected by the conflict.
"All parties to the conflict have a responsibility to make sure that civilians are spared from the fighting," said Lanzer, the UN humanitarian coordinator.
"We call on all parties to facilitate aid agencies' access to civilians, and to protect and respect humanitarian activities."
Almost three weeks of violence has forced around 200,000 people to flee their homes and "affected many hundreds of thousands of people indirectly", Lanzer added.
Some 57,000 are seeking refuge with badly overstretched UN peacekeepers.
The UN peacekeeping force said this week "atrocities are continuing to occur" across the country, which won independence from Sudan in 2011 after decades of civil war.
One of the hardest hit areas is the rebel-held town of Bor, the capital of Jonglei state and situated just 200 kilometres (125 miles) north of the capital Juba, which has changed hands three times since the fighting erupted.
On Thursday, army spokesman Philip Aguer said troops were "advancing again" on the town.
Tens of thousands have fled, many paddling in simple boats across the White Nile river to escape the fighting to Awerial in neighbouring Lakes.
Amid the fighting, the talks in Addis Ababa have been welcomed.
UN special envoy Hilde Johnson stressed the need for "reconciliation and healing".
The conflict has been marked by an upsurge of ethnic violence pitting members of Kiir's Dinka tribe against Machar's Nuer community.
The United Nations reported "extra-judicial killings of civilians and captured soldiers" and the "discovery of large numbers of bodies" in the capital Juba as well as in the towns of Bor and Malakal.
The army has set up committees into the killing of "innocent people", the government said Thursday, and another into the bitter infighting within the presidential guard units that were the reported first shots in the conflict.
On Tuesday, Machar told AFP that he was not yet ready to agree to an immediate ceasefire nor hold face-to-face talks with Kiir.
Kiir has described the war as "senseless", but has ruled out power sharing with the rebels.
"If you want power, you don't rebel so that you are awarded with the power," Kiir said in an interview broadcast on the BBC.