An operation by Ukraine's Security Service (SBU) has hit "more than 40" Russian bombers at air bases "in the rear of the Russian Federation" on June 1.

Axar.az informs, citing Kyiv Independent, "Enemy strategic bombers are burning en masse in Russia — this is the result of a special operation by the SBU," the source said.

"Right now, the Security Service of Ukraine is conducting a large-scale special operation to destroy enemy bomber aircraft in the rear of the Russian Federation.

"SBU drones are practicing on aircraft that bomb Ukrainian cities every night. Currently, more than 40 aircraft are known to have been hit, including the A-50, Tu-95 and Tu-22 M3."

Video provided by the source shows what appears to be a row of heavy bomber aircraft on fire at an undisclosed location.

The source said at least one of the airfields hit was the Belaya air base in Russia's Irkutsk Oblast. The oblasts governor, Igor Kobzev, later confirmed "a drone attack on a military unit in the village of Sredny" but gave no further detials.

Unconfirmed reports on social media said a fire was also burning at the Olenya air base in Russia's Murmansk Oblast.

Murmansk Governor Andrey Chibis later confirmed that "enemy drones have attacked the territory of the Murmansk region" but gave no further details.

The SBU did not say what type of drones were used in the attack but unconfirmed reports on social media suggest some were FPV drones launched from vans parked near the airfields.