Ukraine says its forces successfully hit an oil refinery in the Russian town of Kstovo, around 800 kilometres (500 miles) from the front lines in eastern Ukraine.
Four drones hit a Lukoil company depot, Ukrainian media said, adding that the facility suffered significant damage.
Videos posted on social media showed large flames rising over an industrial facility.
Regional governor Gleb Nikitin said that drone debris had fallen over the industrial zone, and that no casualties had been reported at the scene.
Separately, the governor of the region of Smolensk, Vasily Anokhin, said on Telegram that a “massive” drone attack against “civilian infrastructure” had occurred in his region, although no casualties were immediately reported.
Anokhin said one of the drones had been shot down when attempting to hit a nuclear power facility. The BBC has not been able to verify this information independently.
A mother and her toddler were killed in the border region of Belgorod, which has come under frequent attack from Ukraine since the start of Russia’s full-scale invasion in February 2022.
Vyacheslav Gladkov, the governor of Belgorod region, said another child and his father were also injured in the strike.
The strike on Kstovo, Smolensk and Belgorod were part of a larger overnight attack, in which Russia said it brought down more than 100 Ukrainian drones and which led the airports of St. Petersburg and Kazan to suspend operations overnight.
It is one of the largest Ukrainian operations of its kind during the war and the second massive drone attack this week. On Friday, Ukraine hit another Russian oil refinery and targeted Moscow during an attack involving a wave of at least 121 drones.
As Ukrainian drones swarmed Russia’s skies, Moscow launched an overnight attack of its own, triggering air alerts in various Ukrainian regions.
The Ukrainian army said it shot down 29 Russian drones over nine regions.
As the third anniversary of Russia’s invasion of Ukraine approaches, the conflict grinds on.
Russia is making regular small advances in the east of Ukraine, edging ever closer to the strategically important city of Pokrovsk, which plays a crucial role as a logistics hub used by Ukrainian forces in the region.
Meanwhile, Ukrainian forces continue to hold on to several hundred square kilometres of territory in Russia’s western Kursk region, where they launched a lightning offensive in August.
