The US initially drafted a plan to end the conflict that was heavily criticised in Kyiv and western Europe for being too close to Russia's line, while later proposals were criticised by Moscow for floating the idea of European peacekeepers.

Abu Dhabi hosts trilateral meeting with the U.S., Ukraine and Russia in a possible sign that the nearly four-year war could be coming to an end.

Ukrainian and Russian negotiators met in Abu Dhabi on Friday to tackle the vital issue of territory, with no sign of a compromise, as Russian airstrikes plunged Ukraine into its worst energy crisis of the four-year war.