Abu Dhabi -- Negotiators from Russia, Ukraine and the United States met Friday in Abu Dhabi for the first direct negotiations on a plan being pushed by US President Donald Trump to end the almost four-year-long war.

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.

Ahead of Friday's talks, which are set to continue on Saturday, Ukrainian President Volodymyr Zelensky said territory remained the key issue – with Moscow having said it is not dropping its demand that Kyiv pull out of its eastern Donbas region.

After the first day of talks, Ukraine's chief negotiator Rustem Umerov posted on social media that the meeting had focused "on the parameters for ending Russia's war and the further logic of the negotiation process", adding that meetings were scheduled for Saturday.

The UAE foreign ministry said in an earlier statement the talks were scheduled to last two days and were "part of ongoing efforts to promote dialogue and identify political solutions to the crisis".