Some South Sudanese, including those with dual U.S. citizenship, are not being allowed to leave war-torn South Sudan, even as the United States, India and others continued Thursday to evacuate their citizens while a fragile cease-fire appeared to hold.

The reports that South Sudan’s government is checking the political ties of people, especially of men, who are seeking safety have raised fears of further violence in a country trying to heal from civil war.

An Associated Press reporter at the airport in the capital, Juba, saw local authorities refuse about 20 dual South Sudanese-U.S. citizens from leaving the country, despite the presence of U.S. Embassy staff.

The State Department acknowledged that some people had been barred from boarding a chartered flight.