Russia's Defense Ministry said that four soldiers had been injured by the alleged drone attacks on the Dyagilevo airfield near the city of Ryazan and the Engels-1 military air base in Saratov Oblast on Dec. 5.
Ukraine has neither confirmed nor denied its responsibility for the incidents. If carried out by Ukraine, the attacks are Ukraine's most ambitious inroads into Russian territory so far - 600-700 kilometers from Ukrainian-controlled areas.
Russia's Defense Ministry claimed that it had shot down the drones. They exploded and caused "insignificant damage" to two planes, according to the ministry.
However, there is evidence that the damage could have been significant.
Ukraine's Air Force published two photos of the consequences of the attack on the Dyagilevo airfield. The images show a damaged bomber and a truck with traces of blood next to it.
Russia stations strategic missile-carrying bombers at both airfields, which it uses for attacks against Ukraine.