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

Russia's claims that Ukraine is delaying exchange of soldiers' bodies are untrue, Ukrainian officials said on Saturday, urging Moscow to stop "playing dirty games" and return to constructive work. Kremlin aide Vladimir Medinsky said on Saturday that Ukraine had unexpectedly postponed exchanging prisoners of war and accepting the bodies of killed soldiers for an indefinite period.

Russia and Ukraine wrangled over details of a large prisoner swap, with officials in Kyiv rejecting claims by a Russian negotiator that they were dragging their feet on the planned exchange.