Ukrainian drones carried out an overnight attack on an oil facility in Russia’s Oryol region that is a crucial source of fuel supplies for Russian troops, Ukraine’s military said on Saturday.

The drones hit the Steel Horse production control station, which lies about 170 km (107 miles) from the border with Ukraine, a military statement said.

Earlier, Russian regional governor Andrei Klychko said on the Telegram messaging app that Ukrainian drones had struck a fuel infrastructure facility, causing a fire but no casualties. He said 11 drones had been shot down over the region.

The Oryol region neighbours Russia’s Kursk region where Ukrainian troops control some settlements after Kyiv’s incursion into the Russian territory in August.

Ukraine has stepped up its use of drones this year to attack Russian oil facilities, which it deems legitimate military targets that are aiding Russian troops in their nearly 34-month-old invasion. Moscow calls the attacks “terrorist acts”.