Fresh fighting has erupted in Bor, the contested capital of South Sudan’s Jonglei state, as rebels move to retake control from government troops.
The military action signals that both sides in the conflict are far from reaching the ceasefire deal that regional leaders hoped would be struck before the end of the year.
Government troops are battling renegade forces loyal to former vice president Riek Machar, as well as a pro-Machar tribal militia known as the “White Army”, said military spokesman colonel Philip Aguer.
Bor is a strategic town in the country’s largest state, and it appears both sides want to be in control of it before the start of any direct peace talks.
South Sudan’s government had been warning of a looming battle for Bor, which a rebel commander loyal to Mr Machar briefly took before he was repulsed by government forces.
That pro-Machar commander, Peter Gadet, has mobilised “elements of the White Army” in a bid to retake the town, according to Col Aguer.
Bor is the town where gunfire hit three United States military aircraft trying to evacuate American citizens on Dec. 21, wounding four US service members.
South Sudan has been hit by unrest since December 15, when fighting among presidential guards later spiralled across the country.
Although Juba, the capital, has since become calm, violence persists in other parts of the oil-producing East African country.
Rebel forces still control Bentiu, the capital of oil-rich Unity state, and it appears that they will try to seize Bor from the 2,100 government troops who control the town, Col Aguer said.
Regional leaders under a bloc known as IGAD last week set Tuesday as the deadline for the president Salva Kiir and Mr Machar to start peace talks.
Uganda’s president, Yoweri Museveni, said neighbouring countries would unite to “defeat” Mr Machar if he does not stop his rebellion.
Mr Museveni said regional leaders “shall have to go for” Mr Machar in the event he rejects peace talks, an apparent military threat that raised the danger of a wider regional conflict.
The United Nations and the African Union have said they support IGAD’s diplomatic efforts to end violence in the world’s newest country.
Mr Machar has called for a negotiated ceasefire and wants all his jailed political allies freed before starting talks.
IGAD has named a Kenyan and an Ethiopian as special envoys who will “spearhead mediation and broker peace” between the two factions, according to Ethiopia’s foreign ministry, which added that IGAD members must create an environment “conducive” for both sides to participate in direct talks.
Although Mr Kiir insists the latest unrest was sparked by a coup mounted by soldiers loyal to Machar late on December 15, this account has been disputed by some officials with the ruling party who say violence broke out when presidential guards from Mr Kiir’s majority Dinka tribe tried to disarm guards from the Nuer ethnic group of Mr Machar.
South Sudan has been plagued by ethnic tension and a power struggle within the ruling party that appears to have escalated after Mr Kiir sacked Mr Machar as his deputy earlier this year. Mr Machar has criticized the president as a dictator and says he will contest the 2015 election.
The UN, South Sudan’s government and other analysts say the dispute is political at its heart, but has since taken on ethnic overtones. The fighting has killed more than 1,000 people and displaced up to 180,000, according to the UN.