The decision left officials on both sides of the Atlantic scrambling to find out how long the pause might last.

The Pentagon came under criticism Wednesday for its decision to halt sending air defense missiles to Ukraine, with lawmakers on both sides of the aisle arguing that move was shortsighted at a time when Russia has ramped up its missile and drone barrages.

The move "was made to put America’s interests first," a White House spokeswoman said, as U.S. munitions have been depleted in recent years.