MOSCOW, April 1. /TASS/. The fire at the oil depot in Russia’s Belgorod was caused by an airstrike from two Ukrainian helicopters that entered the Russian airspace, Belgorod Region Governor Vyacheslav Gladkov said in his Telegram channel Friday.

"The fire at the oil depot occurred because of an airstrike from two Ukrainian Air Force helicopters that entered the Russian territory on a low altitude. There have been no casualties," Gladkov said.