Ukraine unleashed more than a hundred drones smuggled deep into Russia in what it called its most damaging attack yet.

With 41 military aircraft impacted, the Ukrainian drone attack was described by some commentators as Russia's "Pearl Harbor." The attack on Pearl Harbor in December 1941 was a surprise air raid by Japan on the U.S. during World War II. Kyiv's assault follows ground advances by Moscow troops in recent days in Ukraine's Sumy border region.

Drones smuggled into Russia hit bases as far away as Siberia and the far east, destroying 41 aircraft that carry cruise missiles and detect enemy planes, said a Ukrainian official.