JUBA: South Sudan's government said Thursday it was battling to retake the key rebel-held town of Bentiu, as thousands of civilians continued to flee fighting across the country.
The ongoing fighting, mainly in the oil-rich north and around Bor in the centre, came as peace talks being held in neighbouring Ethiopia appeared to be deadlocked.
The rebels say they will only agree to a ceasefire if the government frees a group of alleged coup plotters detained after the fighting began more than three weeks ago, although the government has ruled this out.
Army spokesman Philip Aguer told AFP that troops loyal to President Salva Kiir were now "next to Bentiu," capital of Unity State and one of South Sudan's main oil-producing areas, and that clashes were continuing Thursday.
He added that government troops were also some 15 kilometres (nine miles) from Bor, capital of the restive Jonglei state and situated 200 kilometres (130 miles) north of Juba the only other major town in rebel hands.
An AFP correspondent in Minkammen, on the other side of the swamps of the crocodile-infested White Nile river from Bor, said hundreds of people are making a perilous journey by boat and on foot to escape the fighting, joining 80,000 others -- the single largest concentration of people displaced by the conflict.
Many recount tales of horror, including civilians mown down with machine guns as they fled, and gunmen torching entire villages and looting the crops.
"They had a machine gun raised up on a sandbank, and they fired and fired and fired as we swam," said Gabriel Bol, a cattle herder. "The bullets were hitting the water, but we knew we could not stop or they'd shoot us."
In Bentiu, a local resident described an atmosphere of "fear" as civilians brace themselves for an anticipated government onslaught.
Unity State is where much of fledgling oil producer South Sudan's best-quality crude is pumped. The country's oil production has dropped by around a fifth since the fighting began, depriving the impoverished nation of a key source of foriegn currency.
"There are no goods on sale. We are just expecting fighting. Everything is dangerous. People are leaving for their villages in fear," said the resident, who asked not to be named.
The unrest began on December 15 as a clash between army units loyal to President Kiir and those loyal to ex-vice president Riek Machar. It has escalated into war between government troops and a loose alliance of ethnic militia forces and army units who have defected to the rebel side.
The exact toll of the conflict is unclear. The UN has said well over a thousand people have died, although sources from a number of relief organisations say they believe the number of fatalities is well into the thousands.
In Washington, the State Department insisted that talks on a possible ceasefire were making progress, although diplomats have admitted the main stumbling block remains the fate of political prisoners.
"The discussions have made progress on a proposed cessation of hostilities," US State Department spokeswoman Jen Psaki said in Washington.
"Disagreements remain on the issue of the release of political detainees. Obviously, the discussions are continuing, but that's where things stand at this moment," she added.
The government is currently holding 11 of Machar's allies, many of them senior figures and former ministers, and has been under pressure from IGAD -- the East African regional bloc brokering the Addis Ababa talks -- as well as Western diplomats to release them as a goodwill gesture.
The demands have been resisted until now, with the government arguing the detainees should be put on trial for their role in what the president says was an attempted coup.