Residents reported large flames rising from the western side of Rosneft’s Kuibyshev oil refinery in Russia’s Samara region as the plant caught fire again overnight into Sept. 23. Ukrainian drones had struck the refinery the previous morning, but whether the new fire was related to that attack remained unknown, Faytuks Network reported.

Ukraine said it had hit the Kuibyshev refinery, where fires continued into the morning of Sept. 22. The plant processes about 7 million metric tons of oil a year and belongs to Rosneft’s Samara refining hub, alongside plants in Novokuibyshevsk and Syzran. Previous strikes had already forced it to suspend operations in June.