The Biden administration moved Thursday to choke off U.S. exports to three Russian airlines as part of what officials described as an unprecedented enforcement action.

The Commerce Department said the move would prevent the airlines — Russian national flag carrier Aeroflot, Utair and Azur Air — from receiving items from the U.S., including parts to service their aircraft.

“Those restrictions are significant because it’s obviously difficult to keep flying if you can’t service your planes,” Matthew Axelrod, an assistant commerce secretary for export enforcement, told reporters.

The effect, he said, is that the sanctioned airlines “and their fleet of aircraft will, over time, largely be unable to continue flying, either internationally or domestically, as they are now cut off from the international support and the U.S. parts and related services they need to maintain and support their fleets.”

The actions, known as temporary denial orders, do allow the Commerce Department to grant exceptions when the safety of a flight would be at risk. The orders extend for 180 days, though they can be renewed.

The three airlines that were singled out had already violated U.S. government restrictions, and the actions were taken to prevent expected violations in the future, officials said.

The private sector has also taken its own action against Russian airlines in response to the war against Ukraine, with Delta Air Lines in February suspending its codesharing partnership with Russian national airline Aeroflot.