Russia launched a massive attack on Ukraine's Kharkiv, killing four and injuring dozens. President Zelenskyy condemned the violence and appealed for urgent air defense assistance.

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

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.