Ukrainian drones attacked a facility in the western Siberian region of Tyumen, local authorities said Monday afternoon, while independent media reported that Russia’s largest petrochemical plant was targeted.

Tyumen Region Governor Alexander Moor confirmed that a fire broke out after several drones crashed into an industrial facility, although he did not identify the site by name, The Caspian Post reports, citing The Moscow Times.

He also did not provide information on whether anyone was injured.

Unverified reports indicated that the drones targeted the ZapSibNeftekhim plant, part of the Sibur petrochemical giant, in the city of Tobolsk. The facility is located approximately 2,200 kilometers (1,370 miles) from Ukraine’s border.

Videos shared on social media purportedly showed thick plumes of smoke rising above the petrochemical plant.

Ukraine, which said it had struck two Russian oil refineries early Monday, did not immediately claim responsibility for the attack in the Tyumen region.