Ukraine alleged Monday that Russia mixed bodies of its own dead soldiers among the Ukrainian military dead that have been returned, and that more than a million Russians have been killed since conflict began.

Minnesota Governor Tim Walz said a 57-year-old suspect was arrested on Sunday in the killing of a Democratic state lawmaker and her husband while posing as a police officer.

Russia and Ukraine exchanged more prisoners of war on Tuesday, the Russian defence ministry said, without giving details of the numbers involved.