Ukraine has launched one of the most devastating drone strikes on Russian soil since the start of the war, sending shockwaves from Moscow to the front lines.

In the early hours of Sunday morning, Ukraine launched one of the largest drone attacks on Russian territory since the 2022 invasion, with over 500 unmanned aerial vehicles targeting 14 regions of the Russian Federation, according to Russia’s Ministry of Defense, which reported that 556 drones were intercepted between 10:00 PM and 7:00 AM local time.

At least four people were killed in the assault — three in the Moscow region and one in the Belgorod region, Russian authorities announced Sunday.

Moscow’s air defenses destroyed 81 drones approaching the capital after midnight. Mayor Sergei Sobianin confirmed that 12 people were wounded, most of them near the entrance to a Moscow oil refinery, while three residential buildings sustained damage. The technological infrastructure of the refinery was not affected. Debris from intercepted drones also fell on the territory of Sheremetyevo, Russia’s largest airport, without causing damage.

The attack came three days after Russian bombardments on Kyiv, following which President Volodimir Zelensky had promised a proportionate response. Zelensky declared that the drones flew more than 500 kilometers from Ukrainian territory and that Ukraine is “overwhelming” Russian air defense systems concentrated in and around the capital, adding: “Our responses to Russia’s prolongation of the war and its attacks on our cities and communities are fully justified. This time, Ukrainian long-range sanctions reached the Moscow region, and we are telling Russians clearly: their state must end the war.”

Russia’s Defense Ministry announced Sunday morning that it had destroyed 556 drones, and shortly after midday local time reported that over 1,000 drones had been shot down or jammed in the previous 24 hours.