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.

Ukraine and Russia completed the first day of what is expected to be the largest prisoner swap of the war, with each side ultimately expected to get back 1,000 people.Ukrainian and Russian officials said that each side had received 270 military personnel and 120 civilians on Friday.