Russia and Ukraine held a second round of peace talks where they agreed to exchange more prisoners and to return the bodies of 12,000 dead soldiers.

The attacks come days after Trump says Putin had "very strongly" promised response to Ukraine "Spider web" attack.

The Kremlin said on Friday the Ukraine war was "existential" for Russia, after it launched a wave of retaliatory drone and missile strikes that killed at least four people.

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.

The air assault killed at least three people. Kharkiv’s mayor described it as “the most powerful attack” since the beginning of the war.

Russia bombarded Ukraine’s second-largest city with massive strikes in the early hours of Saturday, its mayor said, one night after Moscow carried out one of the war’s largest aerial assaults on Ukraine.