The country's special forces say that two large gas processing plants have been hit by drones in Novy Urengoy and Purovsky in the Yamalo-Nenets region in western Siberia, which is important for the Russian gas industry.
The drones travelled more than 300 miles, according to the Ukrainian military.
"Until today, the area was considered a safe rear zone for the attacker," the special forces wrote in a statement.
Dmitry Artyukhov, governor of Yamalo-Nenets, said on Telegram that the drone heading towards Novy Urengoy was shot down, AFP news agency reports.
Video clips circulating on social media show smoke rising over the city and flames erupting from an industrial plant.
Ukrainian President Volodymyr Zelenskyy recently said that long-range attacks on the Russian energy sector will be further escalated.
In a recent post on social media, Zelenskyy thanked the military for the effort.
"It is important that we respond to Russia's war in a fully justified way - and in a way that the enemy can truly feel. Any such effort reduces Russia's ability to delay the decisions required for diplomacy," he wrote.
