Russia and Ukraine exchanged hundreds more prisoners Saturday as part of a major swap that amounted to a rare 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.

In Kyiv, Timur Tkachenko, head of the city’s military administration, said 11 people were injured in drone strikes. A five-storey apartment building was hit in the Holosiivskyi district just outside the city centre, triggering a fire that damaged the building’s exterior.