The U.S. State Department ordered nonemergency personnel to leave South Sudan’s capital as tensions rise due to northern fighting.

Clashes last week led to the arrests of key officials linked to Vice President Riek Machar, sparking concerns over the country’s fragile peace deal.

A U.N. helicopter evacuation was attacked, prompting warnings from the U.N. that the escalating violence threatens to derail peace efforts, the Associated Press has reported.

Written by B.C. Begley