Mr Trump said that the allies at the NATO summit meeting had agreed to his demand for a significant increase in military spending. But he offered no specifics, and President Emmanuel Macron of France refuted the claim at the end of the NATO summit meeting in Brussels on Thursday.
Mr Trump signed a joint statement that largely reaffirmed existing NATO commitments, and that was at odds with some of his own statements.
On the final day of the talks, Mr Trump turned a heads-of-state meeting with Georgia and Ukraine into an argument about spending, prompting an emergency budget meeting.
President Trump is on a seven-day, three-nation European trip to Belgium, Britain and then Finland for talks with President Vladimir V. Putin of Russia that highlights the ways he has utterly transformed United States foreign policy.