LONDON (AP) — Britain is evacuating its citizens from South Sudan amid escalating violence in the young East African country.

The Foreign Office says a plane is on the way to the South Sudanese capital, Juba, on Thursday following reports of a coup attempt.

It said more than 150 Britons had contacted the government wanting to leave.

The evacuees include some British embassy staff, though the embassy remains open.

The United Nations has estimated that up to 500 people have been killed in fighting between rival factions following a coup attempt against the president by soldiers loyal to his former deputy.

U.N. secretary-general Ban Ki-moon has said that around 20,000 people have taken refuge with the U.N. in Juba.

The United States evacuated 120 diplomats and other U.S. nationals on Wednesday.