The airfield in the Kursk region was shelled on December 6, the other two - on December 5.
"These were Ukrainian drones - very successful, very effective", - The Washington Post quoted the interlocutor as saying.
The source does not give details, and official Kyiv did not admit its involvement.
On December 5, three Russian soldiers were killed in an attack in the Ryazan and Samara regions. The drones were intercepted by air defense systems. Due to a drone attack on December 6, classes in two schools were canceled in the Kursk region.