Four people were killed and more than 50 injured in Ukraine after Russia pummeled targets across the country with drones and missiles for a second straight night.

Ukraine denied Russian allegations on Saturday that it had indefinitely postponed prisoner swaps, accusing Moscow of "playing dirty games" after overnight Russian missile and bomb strikes on Kharkiv left three people dead and 22 injured.

Ukraine says that a large Russian drone-and-missile attack has targeted the eastern city of Kharkiv, killing at least three people and injuring 21