Russia downed 31 Ukraine-launched drones overnight over the regions of Belgorod, Bryansk and Kursk bordering Ukraine, the defence ministry said on Wednesday.
There was no information about potential casualties or damage.
Separately, Ukrainian forces fired cluster munitions at several villages in Russia's southern region of Bryansk, Governor Alexander Bogomaz said on the Telegram messaging app.
There were no casualties in the attacks, although several homes were damaged, he added.
Reuters was not able to verify the reports. There was no immediate comment from the government in Kyiv.
Ukraine has received cluster munitions from the United States and pledged to use them only to dislodge concentrations of enemy soldiers.
Russian officials in Bryansk and other regions bordering Ukraine have repeatedly accused Ukraine's armed forces of indiscriminate shelling.
Cluster munitions are prohibited by more than 100 countries. They typically release large numbers of smaller bomblets that can kill indiscriminately over a wide area. Those that fail to explode can pose a danger for decades. (Reporting by Lidia Kelly in Melbourne; Editing by Stephen Coates)