Russia, using missiles and drones, launched one of the biggest assaults on the Ukrainian capital, Kyiv, since the beginning of the war more than three years ago and hours after a prisoner exchange began.

Russia and Ukraine have exchanged hundreds more prisoners as part of a major swap that amounted to a moment of cooperation in otherwise failed efforts to reach a ceasefire.

Reuters witnesses saw and heard successive waves of drones flying over Kyiv, and a series of explosions jolted the city.