Russia continued to pound Ukraine even on the eve of Orthodox Christmas.
Two people were killed in Kherson reportedly due to Russian shelling, while missile and drone strikes caused power outages in Donetsk.
Ukraine's military claimed that Russia fired 28 drones, 21 of which were shot down.
It added that Russia also launched three anti-aircraft missiles.
While Russian president Vladimir Putin vowed to back soldiers at the frontline, his Ukrainian counterpart expressed hope that Russia's aggression could be defeated.
More than 100 residents of Russia's border region, Belgorod, have moved farther away from Ukraine.