JUBA, South Sudan -- The United Nations sent four helicopters to evacuate staff from one of its bases in South Sudan's Jonglei state where two Indian peacekeepers and at least 20 civilians were killed Thursday in violence gripping the world's newest nation.
Fighting has spread since the Dec. 15 attack outside an army barracks in the capital, Juba, with the violence leaving as many as 500 people dead while at least 34,000 have sought shelter at UN compounds, according to information from the government and UN.
South Sudan's government lost control of Bor, the capital of Jonglei state, on Dec. 18 to a group linked to former Vice President Riek Machar, who was fired in July and is being hunted by security forces for staging a failed coup this week. While Machar denies that accusation, he's called for President Salva Kiir to step down because he's failed to unite the nation. The violence has heightened ethnic tensions, with Machar's Nuer group pitted against the Dinka people of Kiir.
"The situation in Bor remains a great concern, fighting continues in the city," UN spokesman Joseph Contreras said Friday by phone from Juba.
Land-locked South Sudan has sub-Saharan Africa's third- largest oil reserves after Nigeria and Angola, according to the BP Statistical Review, and exports about 220,000 barrels of oil a day through pipelines across Sudan. Jonglei is an eastern state bordering Ethiopia where Total SA has a stake in an oil- exploration concession.
The UN Security Council expressed "grave alarm and concern regarding the rapidly deteriorating security and humanitarian crisis in South Sudan" and urged Kiir and Machar to find a swift solution, according to a statement Friday.
While the violence hasn't yet affected the flow of oil from South Sudan, now that fighting has reached crude-producing areas, it may do so unless it stops, Sudanese Information Minister Ahmed Bilal Osman said Friday by phone from Khartoum, Sudan's capital.
Three oil workers and three ethnic Dinka civilians were killed Thursday in Unity state, Anjelo Majok, commissioner of Pariang County, said by phone Friday.
Production slowed at the Unity field because of the attacks and output should be returned to pre-attack levels soon, South Sudan Petroleum Minister Stephen Dhieu Dau said by phone Friday. The government is sending forces to secure oil fields and prevent more attacks, he said.
"This situation will be brought under control, shortly," Dau said. "There's no threat to the oil production, so the oil flow is normal."
About 2,000 armed youths believed to be from the Nuer community tried to storm the UN Akobo base in Jonglei state Thursday and opened fire at ethnic Dinka civilians who were seeking refuge there, the UN Mission in South Sudan said Friday in a statement.
The UN and the Sudan People's Liberation Army regained control of the base about three hours after the storming, according to the statement.
Two Indian UN peacekeepers died and a third was critically injured while trying to negotiate with the youths, the mission said. The UN has yet to verify the total death toll and preliminarily estimates show that at least 20 Dinka civilians have been killed, according to the statement.
Two local government officials were also killed at the compound, Twic East County Commissioner Dau Akoi said Friday by phone from Akobo.
About 45 U.S. troops deployed to South Sudan Dec. 18 will remain in the country until the security situation has improved to the point that they "are no longer needed," President Barack Obama said in letter to Congress dated Thursday. The soldiers were sent to protect U.S. personnel and the embassy.
"South Sudan's leaders must recognize that compromise with one's political enemy is difficult; but recovering from unchecked violence and unleashed hatred will prove much harder," Obama said in an e-mailed statement. The "U.S. will remain a steady partner of the South Sudanese people as they seek the security and prosperity they deserve."
African ministers from countries including Kenya and Uganda made a "good start" in talks that are continuing with Kirr, Ethiopian Foreign Minister Tedros Adhanom, who is chairing the consultations, said on his Twitter account Friday.
Machar said in an interview Thursday with Radio France International that he wants Kiir to step down as president as a condition to negotiations, citing Kiir's inability to unite the country. Kiir said on Dec. 18 that he's ready to hold talks with Machar.
In July, Kiir fired his entire cabinet, including Machar, after the former deputy said he will contest the 2015 presidential elections. The country has been ruled by the Sudan People's Liberation Movement, known as SPLM, since it gained independence from Sudan in 2011.