South Sudan Peace Talks Open as Battles Rage

South Sudan's warring parties began negotiations Friday to end nearly three weeks of raging conflict which has left thousands feared dead and taken the world's youngest nation to the brink of all-out civil war.

Fighting intensified as the army moved on a key rebel-held town, even as government and rebel negotiating teams gathered at a luxury hotel in neighboring Ethiopia's capital Addis Ababa.

"We have enough forces who will defeat the rebels within 24 hours," army spokesman Philip Aguer said in South Sudan, with reports of heavy battles involving tanks and artillery on the outskirts of Bor, a dusty town that has already exchanged hands three times since fighting began.

"These forces -- the rebels -- are now retreating back," Aguer said, quashing rebel claims that they had been marching on the capital Juba.

The U.S. embassy in South Sudan ordered a further pullout of staff and urged all citizens to leave on an evacuation flight it had organized because of the "deteriorating security situation."

The ongoing battles prompted the top U.N. aid official in South Sudan, Toby Lanzer, to warn that soldiers and rebels must protect civilians and aid workers, or risk worsening a situation he described as "critical".

However, U.N. teams accessed World Food Program stores in war-ravaged Bor on Friday, with aid to be distributed to civilians, Lanzer said, suggesting the center of town was at least still calm.

But in the calm of the hotel in Addis Ababa, rivals met special envoys from regional nations, ahead of direct talks that sources suggested may not take place until Saturday at the earliest.

Ethiopia's foreign ministry spokesman Dina Mufti said the regional East African bloc IGAD was committed to support the talks "in any way possible", but when asked when a formal meeting between the two sides would take place, said he "cannot predict anything".

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.

Fighting erupted on December 15 when Kiir accused Machar of attempting a coup in the oil-rich but impoverished nation.

Machar denied this, in turn accusing the president of conducting a violent purge of opponents. He has refused to hold direct talks with Kiir.

Fighting has spread across the country, with the rebels seizing several areas in the oil-rich north.

Aid workers have stepped up warnings of a worsening crisis for civilians affected by the conflict in the landlocked country of almost 11 million people.

"All parties to the conflict have a responsibility to make sure that civilians are spared from the fighting," said Lanzer, the U.N. humanitarian coordinator.

The violence has forced around 200,000 people to flee their homes and "affected many hundreds of thousands of people indirectly", he added.

Some 57,000 are seeking refuge with badly overstretched U.N. peacekeepers.

The U.N. 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 Bor, the capital of Jonglei state and situated just 200 kilometers (125 miles) north of Juba.

Tens of thousands have fled, many paddling in simple boats across the crocodile-infested White Nile river to escape the fighting.

The conflict has been marked by an upsurge of ethnic violence pitting members of Kiir's Dinka tribe against Machar's Nuer community, and the army has set up committees to probe the killing of "innocent people".

The United Nations reported "extra-judicial killings of civilians and captured soldiers" and the "discovery of large numbers of bodies" in Juba as well as in the towns of Bor and Malakal.

Machar told AFP this week 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.