They published an image of a bus with blown out windows and a damaged roof.
The number of deadly Ukrainian drone and missile attacks on Belgorod is increasing.
Moscow continues to make gains in eastern Ukraine and has increased its airstrikes and shelling of Ukrainian border areas.
Kiev said Russian attacks overnight had targeted energy facilities in the northern Sumy region and the northeastern Kharkiv region – both of which have seen an increase in attacks over the weeks.
The Ukrainian Energy Ministry said thousands of homes were without power following the attacks.
It said 91 villages in Sumy were without electricity and Kharkiv also suffered power cuts.
The Interior Ministry said Russian shelling targeted school facilities in the village of Zolochiv in the north-eastern Kharkiv region overnight, wounding at least one person.
Kiev also said the number of people injured in Russian shelling on Kharkiv, Ukraine's largest city, had risen by two to 16 a day earlier.
