More than 120 firefighters were trying to extinguish a blaze at an oil depot in the Russian city of Sochi that was sparked by a Ukrainian drone attack, regional Governor Veniamin Kondratyev said early on Sunday on the Telegram messaging app.

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.

An overnight Ukrainian drone attack on an oil depot near Russia’s Black Sea resort of Sochi sparked a major fire, Russian officials said Sunday, as the two countries traded strikes and the Ukrainian president announced a prisoner exchange.