The U.S. stoppage was first reported by Politico. Trump met with Ukrainian leader Volodymyr Zelenskyy on the sidelines of the NATO summit last week and had left open the possibility of sending Kyiv more U.S.-made Patriot air defense missile systems, acknowledging they would help the Ukrainian cause.

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.