Ukraine said over 40 bombers, or about a third of Russia’s strategic bomber fleet, were damaged or destroyed Sunday, although Moscow said only several planes were struck. The conflicting claims couldn’t be independently verified and video of the assault posted on social media showed only a couple of bombers hit.

Ukraine’s large-scale drone attack on Russian air bases thousands of miles behind the front lines is the latest in a long line of daring missions by Ukraine’s forces against its giant neighbor.