Russian negotiators at peace talks in Istanbul demanded Ukraine pull its troops out of all the Ukrainian regions claimed by Moscow before they would agree to a ceasefire, a senior Ukrainian official familiar with the talks told Reuters.

* International recognition that five parts of Ukraine -- the Crimea peninsula annexed in 2014, as well as the Donetsk, Luhansk, Kherson and Zaporizhzhia regions -- are Russian. The U.S. draft had proposed only U.S. de jure recognition for Crimea, and U.S. de facto recognition for Russian-controlled parts of the other regions.

But the two sides failed to broker a temporary cease-fire or a meeting between their two leaders, a sign of how far apart they remain on ending the conflict.