US President Barack Obama has warned that South Sudan stands at the "precipice" of civil war amid spiralling violence, with the UN launching a rescue mission after three Indian peacekeepers were killed.
The United Nations Security Council readied emergency consultations on the rapidly fledgling nation on Friday, amid growing fears the country was sliding towards all-out civil war.
The UN in South Sudan on Friday reported 14 separate sites of fighting or civil unrest, many in the troubled eastern state of Jonglei, with 34,000 civilians sheltering in or around UN bases.
Obama, who announced he had deployed 45 troops to the violence-racked country, called for an immediate end to the strife.
"Recent fighting threatens to plunge South Sudan back into the dark days of its past," he said.
Over two million people died in the brutal 1983-2005 civil war, which ended in a peace deal that paved the way for the South's independence two years ago.
Recalling the promise and hopes that accompanied South Sudan's independence in July 2011, Obama warned "that future is at risk."
"South Sudan stands at the precipice," the president said, promising that the United States would remain Juba's "steady partner."
India's UN envoy Asoke Mukerji said three Indian peacekeepers were "targeted and killed" during Thursday's attack by ethnic Nuer youths on a base at Akobo in Jonglei state.
Other casualties are feared as the fate of more than 30 ethnic Dinka civilians sheltering at the base is not known, said UN deputy spokesman Farhan Haq.
The UN mission in South Sudan (UNMISS) said on Friday it had sent four helicopters to pull out some 40 UN peacekeepers out of Akobo, saying it has "had received assurances from forces in charge" of the remote town they would not be attacked.
The attack on the UN base came after troops loyal to fugitive former vice president Riek Machar seized the town of Bor late on Wednesday, as heavy fighting continued in several sites across the vast swamplands and remote bush of Jonglei state.
President Salva Kiir has blamed the bloodshed on a coup bid by his perennial rival Machar, who calls that claim a fabrication to cover up a purge by the regime.
Kiir has said he is ready to "sit down," but Machar, who was sacked by the president in July, rejected the offer and called for the president's ouster.
About 450 people have been killed in the capital Juba since battles broke out on Sunday, including around 100 soldiers, the army spokesman said.
The battles have raised concerns of ethnic conflict, with Kiir coming from the majority Dinka people and Machar from the Nuer.
UN human rights chief Navi Pillay has also expressed deep concern over reports of "numerous extrajudicial killings" and "civilians killed in Juba based on their ethnicity."
Human Rights Watch said witnesses had reported horrific cases of both soldiers and rebels executing people based on their tribe, warning of "revenge attacks."
However, the government insists the clashes are over power and politics, noting that both sides include leaders from different tribes.
Foreigners were being evacuated from the troubled country, with the United States and Britain sending in flights for their citizens, and others fleeing overland south to Uganda.
UN chief Ban Ki-moon has warned fighting could spread.
The crisis "urgently needs to be dealt with through political dialogue," he said.
