Ukraine’s capital Kyiv came under a large-scale Russian drone and missile attack overnight into Saturday, just hours after Russia and Ukraine began a major prisoner exchange.

Russia and Ukraine began a major prisoner exchange, swapping hundreds of soldiers and civilians in the first phase of an exchange that was a moment of cooperation in otherwise failed efforts to reach a ceasefire in the 3-year-old war.

Russia and Ukraine began their largest exchange of prisoners of war on Friday, with each side returning 390 soldiers and civilians, according to both governments. More swaps were expected on Saturday and Sunday, as the two countries have committed to exchange 1,000 prisoners each.