Kabul airport is without air traffic control services now that the U.S. military has withdrawn from Afghanistan, and U.S. civil aircraft are barred from operating over the country unless given prior authorization, the U.S. Federal Aviation Administration (FAA) said on Monday.

In a statement, the FAA said that "due to both the lack of air traffic services and a functional civil aviation authority in Afghanistan, as well as ongoing security concerns, U.S. civil operators, pilots, and U.S.-registered civil aircraft are prohibited from operating at any altitude over much of Afghanistan."