Obama warns South Sudan after US aircraft attacked during evacuation

President Barack Obama said Saturday that continued violence and militancy in South Sudan could cost the world's newest country the support of the United States and other nations.

Obama said South Sudan's leaders have a responsibility to protect its citizens and to help protect Americans, who came under fire hours earlier during an evacuation attempt. 

Four American service members were injured Saturday when rebel gunfire hit U.S. military aircraft trying to evacuate American citizens in South Sudan from a remote region that has become a battleground between the country's military and renegade troops, officials said. All four American service members were reported to be in stable condition.

"This conflict can only be resolved peacefully through negotiations," the White House said in a statement Saturday. "Any effort to seize power through the use of military force will result in the end of longstanding support from the United States and the international community."

U.S. Secretary of State John Kerry called President Salva Kirr to urge the South Sudanese leader to avoid ethnic conflict, preserve the welfare of those fleeing the conflict and protect U.S. citizens there. Kerry was sending a special envoy to the region and told Kirr that South Sudan's challenges require leadership and political dialogue, the State Department said.

Air evacuation vehicles were heading to Bor, the capital of the state of Jonglei and scene of some of the nation's worst violence over the last week. 

The U.S. military's Africa Command (AFRICOM) said the three fired-upon aircraft were "participating in a mission to evacuate American citizens in Bor."

"After receiving fire from the ground while approaching the site, the aircraft diverted to an airfield outside the country and aborted the mission," the statement said. 

"The damaged aircraft diverted to Entebbe, Uganda, where the wounded were transferred ... and flown to Nairobi, Kenya for medical treatment," said a follow-up AFRICOM statement.

On Sunday, the State Department said the U.S. citizens in Bor had been safely evacuated to Juba, the capital of South Sudan, adding that it strongly recommends that Americans leave the counrty "immediately."

Meanwhile, the government's foreign minister told Al Jazeera that South Sudan's president is ready to begin talks "with any rebel group" as violence in the country escalates.

South Sudan's Foreign Minister, Barnaba Marial Benjamin, said Saturday, "our president agreed yes, indeed he is willing for talks with the main group. Why would the government not talk to people who were a part of the struggle?"

Officials also told the Associated Press that a separate incident saw a U.N. helicopter take gunfire, also in Jonglei.

South Sudan's military spokesman, Col. Philip Aguer, said that government troops are not in control of Bor, so the attack on the U.S. aircraft has to be blamed on renegade soldiers.

"Bor is under the control of the forces of Riek Machar," Aguer said, referring to the country's powerful opposition figure.

South Sudan's information minister, Michael Makuei Lueth, said that South Sudanese ground troops, backed by the country's air force, are fighting rebels in Bor, an effort to retake the state capital they lost earlier this week.

"There is fighting going on in Bor town, yes, because since (Saturday) morning they have continued to attack the civilian population," he said, talking about renegade troops. "They have gone as far as not respecting the U.N. compound."

The U.N. said 20 people from the ethnic Dinka group were feared killed during an attack by thousands of armed youths from a different ethnic group on a U.N. peacekeeping base in Jonglei state

The ethnic Lou Nuer youths overran the U.N. base in Akobo on Thursday, killing two Indian peacekeepers and fleeing with arms, ammunition and other supplies, the U.N. peacekeeping mission in South Sudan said in a statement.

The Dinka civilians killed had sought refuge at the base.

Lueth said fighting started early Saturday after reports came in that rebels there were shooting indiscriminately at civilians.

"The bodies are sprinkled all over the town," he said, adding that no death toll could be estimated.

South Sudan President Salva Kiir said this week that an attempted coup triggered the violence now pulsing through South Sudan. He blamed the country's former vice president, Machar. The men are from the different Dinka and Nuer ethnic groups who are at loggerheads in the country's festering conflict.

The July ouster of Machar, a Nuer, from the country's No. 2 political position has stoked ethnic tensions.

The ensuing violence has killed hundreds and has world leaders worried that a full-blown civil war could ignite in South Sudan. The south fought a decades-long war with Sudan before a 2005 peace deal resulted in a 2011 referendum that saw South Sudan break away from the north, taking most of the region's oil wealth with it.

Lueth described Machar as "the rebel leader," saying the forces that control Bor believe they are fighting on his behalf. Machar's whereabouts remain unknown, but he has said in recent interviews that he is in hiding in the country.

The U.N. Security Council said Friday that the week-long violence resulted from a "political dispute among the country's political leaders" that could affect not only South Sudan, but neighboring countries and the entire region.

President Barack Obama earlier this week dispatched U.S. troops to help protect the U.S. Embassy in the capital, Juba. The U.S. Embassy organized at least five emergency evacuation flights to help U.S. citizens leave the country. Other countries like Britain, Germany and Italy also helped citizens evacuate.

Al Jazeera and The Associated Press