Russia and Ukraine began a major prisoner exchange Friday, 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.

A large-scale prisoner exchange between Ukraine and Russia, in a 1,000-for-1,000 format, has begun. Today, 390 military personnel and civilians returned from captivity, Ukrainian President Volodymyr Zelenskyy announced.