Russia launched its largest aerial assault of its three-year war on Ukraine overnight, targeting the capital and other regions with missiles and drones for a second night in a row, even as the two sides prepared to conclude a major prisoner exchange.

Fourteen people were reported killed in Ukraine, with its air force saying 22 locations were hit by Russian air strikes.

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