The Ryazan oil refinery, Rosneft’s biggest refinery, was set ablaze, a regional governor said on Wednesday. It shut down two damaged primary oil refining units. Rosneft did not comment. The plant handles about 5.8% of Russia’s total refined crude, according to industry sources.

A fire broke out at Norsi, Russia’s fourth-largest refinery, after a Ukrainian drone attack, Russian officials said on Tuesday. Its main crude distillation unit was damaged, which means that at least half of the refinery’s production is halted, according to industry sources. Norsi handles nearly 6% of Russia’s total refined crude. Before the latest drone attack, one of its two catalytic crackers had already been put out of action.