Russian officials said Sunday that Moscow is still awaiting official confirmation from Kyiv that a planned exchange of 6,000 bodies of soldiers killed in action will take place, reiterating allegations that Ukraine had postponed the swap.

(Reuters) -Ukrainian President Volodymyr Zelenskiy vowed on Sunday to press on with prisoner exchanges with Russia and said any failure by Moscow to uphold humanitarian accords cast doubt over U.S. and other efforts to end the more than three-year-old conflict.

Russia claims Ukraine indefinitely postponed the release while Kyiv maintains it has been delayed until next week.