Ukraine says the Russian military has continued its attacks, despite President Vladimir Putin's declaration of a 36-hour ceasefire.
Putin declared the truce to mark Orthodox Christmas on Saturday.
But the Ukrainian military said on Sunday that Russian forces conducted missile strikes nine times during the ceasefire. It added that the attacks targeted and damaged civilian facilities.
The governor of the Donetsk region in eastern Ukraine, Pavlo Kyrylenko, said in a social media post on Sunday that local facilities had been attacked, including an educational one. He criticized the enemy for not letting up on its aggression.
President Volodymyr Zelenskyy said in a video address released on Saturday that the world has seen "how false any words of any level that sound from Moscow are."
Fierce fighting has continued in the Donetsk and Luhansk regions. Ukraine said it repelled attacks at 16 locations in the east of the country.