JUBA: South Sudan's army was poised for a major offensive against rebel forces, the president said Monday, as the country slid towards civil war despite international peace efforts.
Expectations of a major upsurge in fighting came as the United Nations warned that the situation in the world's youngest nation was fast unravelling, with hundreds of thousands of civilians now at risk.
Fighting has gripped South Sudan for more than a week, after President Salva Kiir accused his former deputy Riek Machar, who was fired from the government in July, of attempting a coup.
Machar denied the claim and accused Kiir of carrying out a vicious purge of his rivals. Vowing to oust Kiir, his forces have since seized the town of Bor, capital of the powder keg eastern Jonglei state and located just 200 kilometres (125 miles) north of Juba, as well as the town of Bentiu, capital of crucial oil-producing Unity state.
The army is "now ready to move to Bor," President Salva Kiir told parliament, adding that the counter-attack to wrest back the town after it was captured on Wednesday was delayed until US had airlifted citizens out.
The comments came despite days of shuttle diplomacy by African nations and calls from the United States, Britain and the United Nations for the fighting to stop.
The UN's top humanitarian coordinator in South Sudan, Toby Lanzer, visited the besieged town of Bor on Sunday, and said the situation was rapidly deteriorating.
"It would have been have been difficult one week ago to imagine that things would have unravelled to this extent," Lanzer told AFP.
"There are hundreds of thousands of South Sudanese who've fled into the bush or back to their villages to get out of harm's way," he said, describing seeing "the harrowing results of the intense violence".
Asked which areas of the conflict-torn country he was most concerned about, Lanzer said that "it would be quicker to talk about which areas I'm not worried about."
"I hope to be wrong, otherwise, hundreds of thousands will need help very soon," he said, adding he was "very concerned that a battle looms" in Bor, where he admitted that the UN peacekeepers were unlikely to be in a position to protect the estimated 17,000 civilians seeking shelter at the UN base there.
The clashes have left hundreds dead -- possibly many more -- and sent tens of thousands of people fleeing for protection in UN bases or to safer parts of the country, which only won independence from Sudan in 2011.
The young nation is oil-rich but deeply impoverished and awash with guns after the long war with Khartoum, and has grappled with corruption and lawlessness since independence.
There are both ethnic and political dimensions to the fighting, as troops loyal to Kiir, an ethnic Dinka, battle forces backing Machar, a Nuer.
Fighting has also spread to Upper Nile state, Medecins Sans Frontieres (MSF) said, with their hospital in Nasir treating 24 people for gun shot wounds on Sunday.
Nuer gunmen stormed a UN base last week killing two Indian peacekeepers and slaughtering at least 20 Dinka civilians who had fled to the compound for shelter, and there have been reports of ethnically-motivated killings and attacks in the capital Juba and elsewhere.
Lanzer said the UN is "fortifying the camp in Bor, making sure there is no repeat of Akobo".
"But, as in Akobo, if there are few peacekeepers inside and 2,000 (fighters) outside, there's little we can do," he warned.
Kiir repeated his offer to hold talks with Machar, adding that the regional bloc, the Inter-Governmental Authority on Development (IGAD), had offered to host talks.
"IGAD has offered to mediate... but I told them that Dr. Riek (Machar) has to come to the table without any precondition," Kiir said.
Foreign governments, including in Britain, Kenya, Lebanon, Uganda and the US, have been evacuating their nationals. On Saturday four US servicemen were wounded when their aircraft came under fire in a rebel-held area.
Britain was flying its third and final military aircraft on Monday to evacuate citizens, warning those who chose to stay "may have difficulty leaving in the event of a further deterioration in security".
Kenya Airways, one of the main commercial carriers to Juba, said they were suspending flights to South Sudan from Tuesday.
UN peacekeepers have said they are also reinforcing their military presence in oil-rich Unity state to help protect civilians. As in Bor, a top army commander in Bentiu switched sides to join the rebellion.
Oil production accounts for more than 95 percent of South Sudan's fledgling economy, and the sector has been hit with oil companies evacuating employees after the death of at least five South Sudanese oil workers last week.
A local official in Bentiu said the area was littered with bodies, while MSF said the hospital there had treated 42 wounded people.
"This Christmas will not be like the previous ones because we will be mourning our dear lost ones in this senseless war," Kiir added.