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.

But halting progress, ever-more deadly drone attacks and unmoving negotiating positions seem to have taken their toll. On Thursday, Trump used a striking analogy to concede the warfare was nowhere near over, and that he did not, at that moment, feel it was best to intervene.

During a visit by the German leader, President Trump essentially threw up his hands, saying that there was nothing the United States could do right now to end the war.