The U.S. move affects high-demand munitions, including Patriot missiles, the AIM-7 Sparrow air-to-air missile and shorter-range Stinger missiles.

Trump gave his first public comments Thursday on the pause in some shipments as Russia escalates its latest offensive.

Analysts say Ukraine’s European allies can fill some of the gaps and provide artillery systems. But they don’t possess alternatives to the U.S.-made HIMARS missiles and air defense systems, especially Patriots, which are crucial to help defend Ukrainian cities.