Russia said Sunday that trains carrying more bodies of Ukrainian soldiers were due to depart toward the Ukrainian border, escalating a spat with Kyiv over a prisoner of war swap. “I can tell you that in just an hour,

Ukraine and Russia, earlier this month, agreed to exchange 1,000 prisoners of war and civilian detainees each in a rare moment of cooperation in more than three years of war.

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.