The first direct talks between Russia and Ukraine since the early weeks of the war lasted just two hours in Istanbul on Friday and only agreed on a prisoner swap — a sign the two sides remain very far apart over ending the conflict.

Ukraine and Western governments want Russia to agree to an immediate, unconditional ceasefire lasting at least 30 days, but a Ukrainian source said Russia's demands were too much.

Ten days of intense diplomatic maneuvers by Europeans and the US ahead of the meeting in Turkey were insufficient to reach a deal, as the differences between the two belligerent parties appear insurmountable.