Ukrainian drone strikes ignited a fire at a major Gazprom oil and petrochemical facility in the republic of Bashkortostan on Thursday, regional officials said.

“Two drones attacked the Gazprom Neftekhim Salavat enterprise,” Bashkortostan regional head Radiy Khabirov wrote on Telegram, describing the incident as a “terrorist attack.” He said security guards at the facility opened fire on the drones.

Emergency crews were working to contain the blaze, Khabirov said, adding that no one was injured in the attack. The extent of the damage remained unclear.

Videos published by Ukrainian media showed what was said to be thick black smoke rising above the site.