The heads of Britain, Italy, Finland and France will join Ukraine's president who is under U.S. pressure to accept a quick deal to end Russia's war on terms that would be hugely difficult to accept.

The traditionally Russian-speaking area is at the heart of what the Russian president calls the “root causes” of the war, and taking it over is near the top of his list of territorial and political demands.

Secretary of State Marco Rubio admitted there would likely need to be some mutual concession of land from Ukraine to Russia in order for a peace agreement to be reached, however Ukrainians find it hard to support such a notion.

The US president will meet his Ukrainian counterpart in Washington on Monday in the wake of his Alaska summit with Vladimir Putin on Friday.

Mike Pence calls for Donald Trump to demand secondary sanctions on Russia after Alaska summit shifts focus from Ukraine ceasefire to broader peace deal.