Trump said he had been "extremely unhappy" with allies' low levels of defense spending before the summit, but was pleased "they have substantially upped their commitment" during a "fantastic" unscheduled crisis meeting on Thursday morning.
Although Trump administration officials point to the longstanding alliance between the United States and the United Kingdom, Trump's itinerary in England will largely keep him out of central London, where significant protests are expected.
Asked about Mr Trump's suggestion, NATO Secretary-General Jens Stoltenberg said he would focus on what has been agreed to.
Mr Trump said he didn't want Russian Federation to be a threat, while adding that his meeting with Mr Putin next week "may be the easiest on his Europe trip".
"And on top of that, they're showing in the future they'll be even closer to Russian Federation because of the pipeline they're putting in", he added. "Everyone in the room thanked me". "The additional money they will be putting up has been really incredible". Very unified, very strong.
Rachel Rizzo, who works on Europe and North Atlantic Treaty Organisation issues at the Center for a New American Security, said that while it is positive that allies have reversed years of decreases in defense spending, pegging defense spending to an arbitrary percentage is problematic. "He does not see the value, and does not recognize that the U.S. also benefits from it".
The U.S. president has taken an aggressive tone during the summit, questioning the value of an alliance that has defined decades of American foreign policy, torching an ally and calling for a massive increase in European defense spending.
It was not immediately clear what specific new commitments had been made. A source close to Macron said Trump had voiced his "personal attachment" to Europe and gave "rather positive and constructive messages" to his allies. They talk about how they are going to increase it [Nato spending] a tiny bit by 2030. He said the increase would happen in "a very short number of years".
"Instead, President Trump just insults friends who have sacrificed to hold that pressure together".
But with tensions in the Western alliance smouldering over Trump's trade tariffs on European steel and his demands for more contributions to ease the burden on United States taxpayers, his earlier remarks fuelled concerns among allies for the U.S. role in keeping the peace that has reigned since World War II. They also agreed in 2014 to each raise their defence spending to 2 per cent of their GDP by 2024. "They pay only a fraction of their cost. We're protecting everybody. And yet we're paying a lot of money to protect". "It confirms the goal of 2 percent by 2024". Allies would be increasing spending by $33 billion or more, he added.
But not before Merkel and other top officials in the German government had publicly fired back at Trump's breakfast diatribe.