Trump's stunning shift in approach to the war and Russia was on full display days earlier when he berated Ukraine President Volodymyr Zelensky in front of reporters at the White House.
Trump's growing closeness with Putin has rung alarm bells across Europe as well as among the US Democratic Party, who have raised national security concerns.
"The White House has become an arm of the Kremlin," said Democratic Senator Chris Murphy, who has emerged as one of Trump's most outspoken critics.
"It appears America is trying to align itself with dictators," he earlier told CNN.
Trump's Republican party, meanwhile, has largely fallen in line behind him, with top officials suggesting Zelensky steps down to ensure a peace deal with Moscow.
"We need a leader that can deal with us, eventually deal with the Russians, and end this war," National Security Advisor Mike Waltz told CNN on Sunday.
