A planned exchange of Russian and Ukrainian prisoners of war failed to take place on Saturday, with Moscow accusing Kyiv of postponing the swap at the last minute, which Ukrainian officials dismissed as more “dirty games” from the Kremlin.

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.

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.