Rebels in South Sudan have attacked two United States evacuation airplanes injuring at least three military personnel.
The aircrafts were shot at in the town of Bor, the capital of Jognlei state, occupied by forces loyal to former Vice-President Riek Machar. Bor has been the scene of heavy fighting this week.
One U.S. service member was in critical condition, reports said. Details of the attack however remain sketchy.
The plane later landed in Uganda.
South Sudan has been in turmoil since Sunday after President Salva Kiir accused Mr. Machar of attempting a coup.
More than 500 people have been killed in days of fighting between troops loyal to the two men, sparking fears the world's newest nation may drift back to its violent past.
The fighting has assumed an ethnic dimension, mainly between Mr. Kiir's majority Dinka people and his former deputy's Nuer ethnic group, the second largest tribe.
Mr. Machar has denied leading a coup, but has made it clear he wants Mr. Kiir out of office.
Several countries, including the U.S, have evacuated their nationals in the past days.
Two Indian peacekeepers were killed on Thursday by thousands of armed Nuer youth who overran a United Nations base to attack Dinka people who sought refuge there.
United States President Barack Obama warned on Friday that the country stands on the precipice and may slide back to civil war.
Mr. Kiir has expressed his willingness to dialogue with rivals to prevent a return to war. His former deputy has not accepted the offer.