Russia has repeatedly hit civilian areas of Ukraine over the course of the war, though it has denied targeting nonmilitary sites. And in recent weeks it has turned up the barrage of missiles and attack drones aimed at Kyiv, the capital. Thousands of Ukrainian civilians, including children, have been killed in Russian airstrikes and artillery bombardments, U.N. officials say.

Though the drone strike on Tuesday was unusual, it was not the first one on Russian soil since the war began. Drones have hit military air bases deep inside Russia, as well as an oil facility near an airfield in the province of Kursk. And this month, drones exploded over the Kremlin.

The incursions continued on Wednesday, when, the Russian authorities said, Ukrainian drones attacked two oil refineries in the region of Krasnodar. They also said that four people had been injured by shelling in the border region of Belgorod.

Russia has long accused the West of waging a proxy war against it. Those claims grew louder this month when a group of Ukraine-based Russian paramilitary members staged a multiday raid in Russia’s Belgorod border region — apparently with U.S. armored vehicles.