The U.S. issued orders suspending Aeroflot PJSC, Russia’s biggest airline, and two others from receiving U.S. parts and services for their planes, a step that officials expect over time will limit their ability to fly.

The denial orders for Aeroflot, Azur Air, and UTair Aviation PJSC announced by the Commerce Department on Thursday mark the first enforcement action for violation of U.S. export controls imposed over Russia’s invasion of Ukraine in late February.

The move comes after some of the airlines’ planes were previously identified by Commerce among more than 100 commercial and private planes of U.S. origin that kept flying to or within Russia without authorization.

The airlines “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,” Matthew Axelrod, assistant secretary for export enforcement at Commerce’s Bureau of Industry and Security, told reporters on Thursday.

The action against the Russian airlines is the latest in a string of sanctions against the nation following allegations of atrocities in Ukraine by Russian forces. On Wednesday, the U.S. announced penalties on two of Russia’s largest banks and President Vladimir Putin’s daughters.

Azur Air’s fleet of 34 planes is composed entirely of Boeing Co. planes of U.S. origin, which means the company won’t be able to service or maintain them and likely will stop the carrier from flying altogether, a Commerce officials said. For UTair, 48 out of their 63 planes are of U.S. origin, while for Aeroflot it’s 59 out of 187.

While UTair and Aeroflot fly some planes that aren’t made in the U.S.—mainly Airbus SE—those aircraft could be affected too if more than 25% of their value comes from American content subject to export controls, the officials said.