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.

Russia said on Wednesday its air defences shot down more than 370 Ukrainian drones, including some approaching Moscow, and the capital's airports were briefly shut down to ensure the safety of flights.