Videos showed helicopters firing rockets at a fuel storage depot in Belgorod, followed by an explosion, as Ukraine attacked a fuel depot in western Russia earlier this week. It was Ukraine's first reported strike from a manned aircraft on Russian soil.
Russia has not reported manned airstrikes on its territory since the Korean War in the 1950s, according to the report. Ukraine is believed to have used Mi-24 choppers to carry out the strike.
The footage showed a light flash accompanied by an explosion in the ground, which appeared to be a rocket launched from low altitude.
According to Belgorod region governor Vyacheslav Gladkov, the fire was caused by an airstrike conducted by Ukrainian helicopters that flew over Russian territory at low altitude.
Two employees at the storage facility were injured in the fire, he said.
The Ukrainian government refused to confirm or deny responsibility for the massive fire at the fuel depot in Belgorod.
Belgorod is located about 80 kilometers northeast of Kharkiv, a heavily fortified city that has been attacked repeatedly by Russian forces since Moscow sent troops into Ukraine on February 24. Belgorod has been used as a logistics base for Russian forces fighting in eastern Ukraine.