Russian forces have the advantage on the battlefield, so a decision by Mr. Putin to settle rather than try to conquer more of Ukraine should be seen as a concession in itself, said Feodor Voitolovsky, director of the Institute of World Economy and International Relations, a Russian government-funded research group.

Even with Trump's direct involvement, Moscow's preconditions for a ceasefire in Ukraine make it a swift ending to the bloodshed difficult to reach.

TRUMP-PUTIN MEETING: The Kremlin said Vladimir Putin and Trump will meet in the ‘coming days’ after the U.S. president said he hoped to hold a meeting with his Russian counterpart in person to discuss ending the war in Ukraine.