KYIV, Ukraine—Russia’s factories have begun churning out vast quantities of attack drones over the past year, producing a deadly fleet that is now taking to Ukrainian skies in record numbers almost daily.

An assault Wednesday was the largest yet, according to Ukrainian officials. In the early morning hours, Russia launched 728 drones and decoy munitions at cities in western Ukraine. The attacks came just hours after President Trump blasted Russia for dragging its feet over peace talks to end the war, saying the U.S. gets “a lot of bulls—” from Russian President Vladimir Putin.