The United States has evacuated hundreds of people from fighting in South Sudan amid fears the country is on the brink of civil war. In a letter to congressional leaders, Obama warned he “may take further action to support the security of U.S. citizens, personnel and property.” He said 46 U.S. troops took part in the evacuation effort, adding to the 45 already deployed to protect the U.S. embassy in Juba. Four U.S. troops were wounded Saturday when their aircraft came under fire. Meanwhile, the United Nations mission has relocated its non-essential staff from the flashpoint town of Bor. U.N. Humanitarian Coordinator Toby Lanzer described the situation there.

Toby Lanzer: “So I’ve just got back from Bor in Jonglei. Situation up there is very, very tense. We spent most of the day evacuating wounded, evacuating citizens of various countries. As I left our base and went to the airport in Bor, yeah, there was a lot of looting, a lot of gunshots, a lot of dead bodies, and very, very out-of-control youth, heavily armed. And that needs to be brought under control.”

The violence erupted earlier this month when President Salva Kiir accused his former deputy of mounting a coup. Rebels allied with the former vice president have now taken control of key areas including two state capitals.