Ukrainian drones have attacked a facility in western Siberia’s Tyumen region, local authorities said Monday afternoon, with independent media reporting that Russia’s largest petrochemical plant was struck.

Ukrainian drones sparked massive fires at the Syzran and Ilsky oil refineries early Saturday morning during an unprecedented overnight barrage across Russia.

In the Tyumen region, the central gas fractionation unit at a Tobolsk plant, which is part of Russia’s largest petrochemical holding company SIBUR, was damaged in a drone attack.…