A diplomatic scramble unfolded Saturday after President Donald Trump announced he would meet his Russian counterpart, Vladimir Putin, next week in Alaska, as European leaders rushed to understand the terms of the meeting and ensure Ukraine was not being left out of discussions about its future.

European nations have rallied behind Ukraine, saying peace in the war-torn nation can’t be resolved without Kyiv.

U.S. NATO Ambassador Matthew Whitaker said President Trump will have to “trust but verify” Russian President Vladimir Putin during their meeting in Alaska on Friday, where they plan to hold talks about ending the war with Ukraine.