A surge in violence between Russia and Ukraine left three dead in Kharkiv and sparked drone attacks in Moscow. Both countries exchanged accusations following separate drone strikes, and discussions on prisoner swaps remain contentious.

Russia pummeled Ukraine's second-largest city, Kharkiv, overnight Saturday, using a swarm of drones, bombs and missiles that killed at least three people, according to local authorities. It was the latest in an escalating series of Russian air assaults on urban centers that have further dampened hopes for a ceasefire.