The summit came as transatlantic ties are already under strain due to U.S. trade tariffs, along with fears that Trump's summit on Monday with Russian President Vladimir Putin will pull him further from Nato's orbit.
The Pentagon did not respond to NBC's request for comment, but a senior administration official told the news outlet that Trump had echoed his public rhetoric about North Atlantic Treaty Organisation commitments in private "aggressive" meetings with leaders of North Atlantic Treaty Organisation member nations.
"They agreed to pay more and they agreed to pay it more quickly", he said, though he did not name countries or give a timeline or figure.
"So if you go back 10 or 20 years, you'll just add it all up". On day two he stated that the United States' commitment to the alliance remains "very strong".
"The communique is clear: it reaffirms the commitment to two per cent (of GDP)", said Macron, who was photographed smiling and sharing a hug with Trump yesterday despite recent tensions between the two. But I will tell you this: at a certain point they're going to call me they're going to say "Let's make a deal".
The US president made an explosive intervention into British politics in an interview with The Sun published Thursday.
Sources close to the talks told DW's Teri Schultz that Trump demanded European NATO members meet the alliance target immediately, rather than increase spending gradually as agreed to at a previous NATO summit in 2014.
Trump has taken an aggressive tone during the summit, questioning the value of a military alliance that has defined decades of American foreign policy, torching an ally and proposing a massive increase in European defence spending.
"I am very happy that today we are united in freedom as the Federal Republic of Germany", she said.
He also reportedly said that if the accelerated target - which was originally agreed for 2024 - is not honored the United States would "do our own thing", sources told the New York Times and Washington Post.
Right before his departure, Donald Trump gathered reporters for an impromptu press conference - never good.
President Donald Trump walks with Turkish President Recep Tayyip Erdogan in Brussels. "Are we contributing the kinds of resources and demonstrating the kind of commitment to the alliance that always needs to be there?" "Supplies of pipeline gas do not lead to dependence of one country on another but to complete mutual dependence".
Says Stoltenberg: "We have agreed that we're committed to the pledge increasing defence spending to 2 percent".
Under fire for his warm embrace of Russia's Vladimir Putin, Trump turned a harsh spotlight on Germany's own ties to Russian Federation, declaring Wednesday that a natural gas pipeline venture with Moscow has left Angela Merkel's government "totally controlled" and "captive" to Russian Federation.
He also said meeting the queen would be an experience Trump "will really cherish". But with Trump scheduled to meet with President Vladimir Putin of Russian Federation on Monday, the gathering was dominated by wrangling over money. And we made clear, well, I made clear for myself and others also made it clear, that we are on this path, which is in our own interest and can make us overall stronger.