MOSCOW, Russia -- Russia said it downed two Ukrainian drones flying over border regions on Sunday, after the governor of Belgorod region said a drone carrying explosives had killed a man.

Russia and the Moscow-annexed Crimean peninsula have been hit by a wave of attacks in the past month, since Kyiv warned in July it aimed to "return" the conflict to Russian territory.

"(During) the night and morning hours... Two unmanned aerial vehicles were detected and destroyed in flight over the territory of the Bryansk and Kursk regions," Moscow's defence ministry said.

The governor of Russia's Kursk region, which lies next to the Ukrainian border, said a drone had crashed into an apartment building in Kursk city overnight, blowing out windows on several floors.

It was not clear whether this was one of the drones reportedly shot down by the defence ministry earlier.

"There were no fires, none of the residents were injured," governor Roman Starovoit said on social media, sharing an image of what appeared to be a charred mark on a tower block.

The attack came a day after the governor of Russia's neighbouring Belgorod region said a drone attack killed a man in the village of Shchetinovka, less than one mile (about two kilometres) from the Ukrainian border.

"The Ukrainian armed forces dropped an explosive device from a drone when the man was on his dacha plot cutting grass," governor Vyacheslav Gladkov said Saturday evening, announcing the man died from shrapnel wounds.

Russian regions bordering Ukraine have regularly accused Kyiv's armed forces of indiscriminate shelling and occasional cross-border incursions by Ukrainian-backed militants.

Ukraine does not claim responsibility for individual attacks on Russian soil and blames the incursions on partisan groups opposed to President Vladimir Putin.