President Volodymyr Zelensky of Ukraine said he would meet with President Trump in Washington on Monday. Mr. Trump and President Vladimir V. Putin of Russia held talks in Alaska but announced no agreement on ending the war in Ukraine.

The uncertainty over what the Alaska talks could produce has raised fears in European capitals that Trump and Putin might take major decisions without Kyiv's involvement.

The unpredictability of how the Alaska meeting will play out has fueled fears that the U.S. and Russia could coerce Ukraine into an unfavorable deal.