The question of how to guarantee Ukrainian security loomed over a meeting of NATO foreign ministers in Norway and a gathering of European leaders in Moldova.
Ukraine is firing artillery shells faster than manufacturers can make them. Brussels is working on a plan to increase production by guaranteeing big advance purchases.
One of Ukraine’s biggest problems in fighting the Russian invasion is a basic one: It is firing artillery rounds much faster than its Western backers are producing them.
In a war where the vital weapons and tactics have changed repeatedly, Ukraine relies more than ever on air defenses to fend off barrages aimed at its energy systems and cities.
American officials said they hoped the commitment would spur allies to make similar donations, as many Ukrainians head into winter without power or water.