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.

It would be the first summit between the leaders of the two countries since Putin met Biden in 2021. Trump has threatened new sanctions against Russia and countries that buy its exports if there is no deal to end the Ukraine war.