Air assaults on Saturday killed at least four people. Kharkiv’s mayor described an overnight strike as “the most powerful attack” since the beginning of the war.

Russia claims Ukraine indefinitely postponed the release while Kyiv maintains it has been delayed until next week.

Overnight missile and bomb strikes by Russia on the Ukrainian city of Kharkiv left three people dead and 22 hurt, while a Ukrainian drone attack in the Moscow region wounded two people, officials from both countries said separately on Saturday.