A fire at Russia's Novoshakhtinsk refinery in the Rostov region began after two Ukrainian drones were spotted over the plant, TASS cited an unidentified source in the local authorities.
"One of them made an impact, crashing into a heat transfer unit, after which the blaze started. The second one flew away," the source told TASS.
The local emergency service said the blaze has been put out, Interfax news agency reported.
(Reporting by Reuters)