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.

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

Ukrainian authorities are enlisting European help to increase domestic military production as the United States pauses some weapons shipments to Ukraine