After Mr. Trump expressed frustration with Russia’s refusal to stop the war, Mr. Putin ordered a three-day cease-fire to begin on May 8, in order to mark the May 9 celebration of the Soviet Union’s victory over Nazi Germany in World War II. Mr. Zelensky described that pledge as a “ manipulation .”

The Russian president had been challenged by Ukraine's Volodymyr Zelensky to meet in person at the talks on Thursday.