Russia’s Lukoil-Nizhegorodnefteproekt refinery has halted crude oil processing following a Ukrainian drone attack.

Axar.az reports, citing Russian media, that the refinery is Russia’s fourth-largest oil refinery and second-largest gasoline producer.

“Several processing units, inter-unit infrastructure and general refinery facilities were damaged in the drone attack. It is not known how long it will take to repair the damage and resume refining operations at the plant,” the report said.

All of Lukoil’s major oil refineries in Russia are currently out of operation, according to the report. The Volgograd refinery halted operations on July 31 following a drone attack, while the Perm refinery stopped operating after a drone attack on August 21.