South Sudan factions arrive in Addis Ababa for cease-fire talks

Members of the South Sudanese opposition arrived in the Ethiopian capital Addis Ababa on Wednesday for talks to end more than two weeks of bloodletting that has threatened to plunge the world's newest country into civil war.

The U.N. envoy to South Sudan, Hilde Johnson, said government negotiators were also on their way. Both sides are under mounting pressure from regional and Western powers to reach a deal to end fighting.

The White House has said it would deny support — vital in a country that still has little infrastructure more than two years after its formation as a nation — to any group that seizes power by force.

Both sides have agreed in principle to a cease-fire but neither has indicated when the fighting would stop. Mediators are concerned that fighting around the flashpoint town of Bor, will scupper the talks even before they begin.

South Sudan's defense minister said on Wednesday that government forces were fighting opposition fighters 11 miles south of Bor, the capital of Jonglei state, which has untapped oil reserves and was the site of an ethnic massacre in 1991.

"There will have to be a fight because they want to defeat the government forces," Defense Minister Kuol Manyang Juuk told Reuters from the capital Juba.

South Sudanese President Salva Kiir declared a state of emergency on Wednesday in two states, according to the government's official Twitter account.

The decree covers Unity and Jonglei, where government troops and rebel forces loyal to Riek Machar, former vice president, have been engaged in fighting.

The Addis Ababa talks will focus on finding ways to roll out and monitor the ceasefire, according to the East African Intergovernmental Authority on Development (IGAD), which is mediating the talks.

The goal is to end fighting that has killed at least 1,000, unsettled oil markets and raised fears of the conflict spilling over in a fragile region. Fighting is also going on in other fronts like Mayom and Malakal, Juuk said.

"We don't want to expose the people of South Sudan to a senseless war," South Sudan's Foreign Minister Barnaba Marial Benjamin said on a government Twitter feed on Wednesday.

South Sudan's neighbors, the U.N. and Washington played a central role in negotiations that ended decades of war and led to the secession of South Sudan in 2011. They have been scrambling to stem the latest violence.

South Sudan holds the third-largest oil reserves in sub-Saharan Africa after Angola and Nigeria, according to BP, but remains one of the continent's least developed countries.

President Kiir has accused his long-term political rival Machar, who he fired in July, of starting the fighting in a power bid.

Machar has denied the charge, but he has taken to the bush and has acknowledged leading soldiers fighting Kiir's government.

Clashes between soldiers erupted on December 15 in Juba. The violence quickly spread to oil-producing areas, dividing the country along the ethnic lines of Machar's Nuer group and Kiir's Dinkas.

On Dec. 24, the U.N. announced that a mass grave had been found in Bentiu, capital of oil-rich Unity state, containing about 75 bodies — sparking fears of renewed ethnic violence.

Machar ally Rebecca Nyandeng, a senior figure within the ruling Sudan People's Liberation Movement (SPLM), which her late husband John Garang founded, told Reuters that Machar's delegation to the talks would be led by former Unity state governor Taban Deng Gai.

Gai was a long-serving governor until Kiir fired him along with Machar in July. 

The White House upped the pressure for the talks on Tuesday.

"We will hold leaders responsible for the conduct of their forces and work to ensure accountability for atrocities and war crimes," spokeswoman Caitlin Hayden said.

Fighting across the country has displaced at least 180,000 people, according to the United Nations.

The clashes have revived memories of the factionalism in the 1990s within the SPLM, the now ruling group that fought Sudan's army in the civil war. Machar led a splinter faction at the time and Nuer fighters loyal to him massacred Dinkas in Bor.

Al Jazeera and wire services