Four US service personnel on an evacuation mission have been wounded after their aircraft were shot at in South Sudan, the US military says.
The three CV-22 Ospreys were attacked as they approached Bor, which is occupied by forces loyal to the former Vice-President Riek Machar, it added.
South Sudan has been in turmoil since President Salva Kiir accused Mr Machar a week ago of attempting a coup.
Mr Machar said that the rebels were under his control.
He was in control of large parts of the country, he said, and troops loyal to him had also seized control of Unity, a state on the border with Sudan which produces much of the country’s oil.
He added that he was prepared to negotiate with the government if politicians arrested earlier this week were released.
At least 500 people have been killed since the fighting began.