The attack so near a NATO member-country raised the possibility that the alliance could be drawn into the fight, and was heavy with symbolism in a conflict that has revived old Cold War rivalries and threatened to rewrite the current global security order.

More than 30 Russian cruise missiles targeted the sprawling facility at Yavoriv, which has long been used to train Ukrainian soldiers, often with instructors from the United States and other countries in the Western alliance. Poland is also a transit route for Western military aid to Ukraine, and the strikes followed Moscow’s threats to target those shipments.