Trump has appeared increasingly exasperated over Russia’s refusal to halt the bombardment of Ukrainian cities.

Prime Minister Mark Carney and Ukrainian President Volodymyr Zelenskyy spoke by phone Monday, reaffirming their agreement that Ukraine must be a party to any discussions about a possible end to the war in that country.

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.