He said 45 military personnel had been deployed to South Sudan on Wednesday to protect American citizens and property.
At least 500 people are believed to have died since last weekend, when President Salva Kiir accused his ex-deputy Riek Machar of a failed coup. An estimated 34,000 people have taken refuge at United Nations compounds.
Three Indian peacekeepers were killed on Thursday when a UN base sheltering refugees came under attack near South Sudan’s eastern border with Ethiopia. Sudan suffered a 22-year civil war that left more than a million people dead before the South became independent in 2011.
The recent unrest has pitted gangs from the Nuer ethnic group of Mr Machar against Dinkas – the majority group to which Mr Kiir belongs. “South Sudan stands at the precipice. Recent fighting threatens to plunge South Sudan back into the dark days of its past,” President Obama said in a letter to Congress.
“Inflammatory rhetoric and targeted violence must cease. All sides must listen to the wise counsel of their neighbours, commit to dialogue and take immediate steps to urge calm and support reconciliation.” On Thursday three Indian peacekeepers died in an attack on a UN compound at Akobo, Jonglei state.
Announcing the deaths at a UN meeting in New York, India’s UN Ambassador Ashok Mukerjisaid they were “targeted and killed” during Thursday’s attack by ethnic Nuer youths on the base. UN deputy spokesman Farhan Haq said more casualties were feared, and he did not know the fate of more than 30 Dinka civilians sheltering at the base. Security at the compound has since been increased. The UN has sent helicopters to evacuate its staff.
President Kiir has blamed the violence on soldiers who support Mr Machar. Mr Machar, who was sacked by Mr Kiir in July, has denied trying to stage a coup. Mr Machar’s whereabouts are unknown. Despite calls for calm, the rival groups have been fighting fierce gun-battles over the town of Bor, in Jonglei state north of Juba. African Union spokesman Ateny Wek Ateny said on Thursday that Bor was in the hands of forces loyal to Mr Machar.
“They control the town but government forces are trying to retake it,” he said. In a statement, the UN mission in the country, Unmiss, said conditions for displaced people in Juba and Bor were “challenging”. It said in some of the UN bases, some people had been able “to construct basic shelters with available materials, but many have no or limited access to shelter”.
A delegation of East African foreign ministers has travelled to Juba to try to mediate in the crisis. South Sudan’s government insists the clashes are over power and politics, not between ethnic groups. The oil-rich country has struggled to achieve a stable government since becoming independent.