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 have completed the first phase of what is expected to be the biggest prisoner exchange since the start of the war, with almost 800 people released on Friday.

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.