A drone attack damaged Yanos oil refinery in Russia's Yaroslavl region, while 65 drones were shot down, Governor Mikhail Yevrayev said in a Telegram post on Thursday.
The refinery sustained damage and fires broke out, but crews quickly extinguished them, while Yevrayev said the attack caused no casualties or injuries.
In a follow-up post, Yevrayev said crews had fully extinguished the fires at the refinery.
The strike hit AVT-3, the refinery's main crude distillation unit, with daily processing capacity of 17,140 metric tons, equivalent to roughly 40% of the facility's total throughput, Reuters reported Thursday, citing four industry sources.
Slavneft owns YANOS, with Rosneft and Gazprom Neft sharing control, while the refinery can handle 300,000 barrels per day and 15 million metric tons of crude annually, according to the report.
Yanos did not immediately reply to' request for comment.