Ryazan oil refinery, operated by the Rosneft oil company, has halted around half its refining capacity since August 2 following a Ukrainian drone attack last week, three industry sources said.

Russia's Ryazan oil refinery halved its production and the Novokuibyshevsk refinery halted it completely on Aug. 2 after Ukrainian drone attacks, Reuters reported, citing undisclosed sources.

CDU-3 (capable of cracking 8,600 tons of crude per day) and CDU-4 (11,400 tons per day)—were shut down on Aug. 2. The refinery now operates only CDU-6, which accounts for roughly 48 percent of its total capacity.