Ukrainian overnight drone attacks have set several non-residential buildings on fire in Russia’s Kaluga and Bryansk regions, regional governors said on Sunday.

“Emergency services and firefighters are on the site,” Alexander Bogomaz, governor of the Russian border region of Bryansk, wrote on the Telegram messaging app, without providing further detail.

The defense ministry said its air defense units had destroyed 23 Ukrainian drones overnight, including 17 over Bryansk.

Vladislav Shapsha, governor of the Kaluga region, which borders the Moscow region to its northeast, said a non-residential building in the region was on fire as result of Ukraine’s drone attack. Reuters could not independently verify the reports. There was no immediate comment from Ukraine.

Kyiv has often said its drone attacks on Russian territory are aimed at infrastructure key to Moscow’s war efforts and are in response to Russia’s continued attack on Ukraine’s territory.