And then numerous of the countries go out and make a pipeline deal with Russian Federation where they're paying billions of dollars into the coffers of Russian Federation.
In a series of tweets from Brussels, Trump said "Presidents have been trying unsuccessfully for years to get Germany and other rich NATO Nations to pay more toward their protection from Russian Federation".
As well as Merkel, Spanish Prime Minister Pedro Sanchez and Charles Michel, the prime minister of Belgium, were also singled out by Trump for undershooting on their spending targets when USA taxpayers, funding a defense budget worth about 3.6 percent of their national income, foot much of NATO's bills.
The Brussels meeting comes less than a week before Mr Trump is due to hold his first summit with Vladimir Putin, in Helsinki, reviving concerns among United States allies over his proximity to the Russian president. "They are a very strong people".
A source close to French President Emmanuel Macron said Trump had voiced his "personal attachment" to Europe and gave "rather positive and constructive messages" to his allies.
"We had a very intense summit", Merkel told reporters after the session.
Trump has spent weeks berating members of the alliance for failing to spend enough of their money on defense, accusing Europe of freeloading off the USA and raising doubts about whether he would come to members' defense if they were ever attacked.
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.
Reporters there noted that Kelly looked fairly uncomfortable as Trump made the comments.
Stoltenberg said it had been appropriate and understandable for defence spending to fall after the end of the Cold War, but the alliance had now recognised the need to bring it back up, with member countries adding billions to their defence budgets.
"The United States is spending far too much and other countries are not paying enough, especially some".
The White House said in a statement to The Washington Post on Wednesday that chief of staff John Kelly looked "displeased" during part of the North Atlantic Treaty Organisation summit in Brussels "because he was expecting a full breakfast and there were only pastries and cheese".
Peter Navarro, director of the White House National Trade Council, echoed Trump's rhetoric, telling Fox Business Network that "Germany is a tremendous problem, both for Europe itself, and for the United States in this sense".
Stoltenberg agreed there should be more done to prompt allies to invest more in their defense.
Brussels is the first leg of a weeklong European tour that will include stops in London and Scotland, as well as a highly anticipated meeting next week with Russia's Vladimir Putin.
Mr Tusk recalled that the Europeans are spending more than Russian Federation and as much as China on defence.