A drone attack in Russia's Belgorod Oblast on May 6 reportedly killed six people and injured at least 35, Governor Vyacheslav Gladkov claimed.
Gladkov said that drones had struck vehicles transporting workers to a factory near the village of Berezovka, and that six people died on the spot.
The information could not be independently verified, and Ukraine does not usually comment on purported attacks on Russian soil.
Belgorod Oblast borders Ukraine's Sumy, Kharkiv, and Luhansk oblasts. Claims of rocket or drone attacks against the region have recently become a common occurrence after anti-Kremlin Russian militias' incursions into the border areas.
Russia reportedly often uses Belgorod Oblast as a launching ground for cross-border missile strikes against Ukraine.