"Now it's no longer obsolete". His comments came during a visit to the White House by NATO Secretary-General, Jens Stoltenberg.
Stoltenberg also said Trump's administration is "very supportive of the adaptation of NATO" that has drawn an increased military presence into the alliance's eastern regions, closer to the border with Russian Federation.
Only days ago, in an interview with the Financial Times, Trump reiterated that campaign pledge. Trump appeared to agree.
Trump' former national security adviser, retired General Michael Flynn, was forced to resign on February 13 for contacts with Russia's ambassador to the United States before Trump took office.
The president, standing in the East Room alongside Stoltenberg, said North Atlantic Treaty Organisation members must "meet their financial obligations and pay what they owe".
Are you confident, though, that that is going to continue in the way that you and President Trump say that it needs to?
The new tone on foreign policy comes as Trump has been trying to settle the palace intrigue inside the White House, where Bannon, former chief of the conservative Breitbart News organization, has been at odds with the more mainstream Jared Kushner, the senior White House adviser who is Trump's son-in-law. That attack prompted a retaliatory USA missile strike. They include billionaire real estate developers Richard LeFrak and Steven Roth, who are informally advising him on infrastructure, and billionaire investor Stephen Schwartzman, the chairman and CEO of the Blackstone Group, who helped organize two major business panels this month to weigh in on possible regulatory and tax changes. "We have to find ways to live with them and to try and avoid a new Cold War, a new arms race", Stoltenberg said. "Instinctively, you would say, 'Isn't that a ridiculous thing, ' but actually, it's a very good thing".
Lawyer: Little money involved in sanctuary order
President Trump has repeatedly said that the actions of sanctuary cities allow risky criminals back on the street. Readler's statements were the first indication that Trump's executive order might have little bite.
But there has been progress on that front, too. After his first meeting with Putin, Bush said he "looked the man in the eye" and "found him very straightforward and trustworthy", getting a "sense of his soul". "He has helped by having such a strong focus on the importance of burden sharing and defense spending". Not Trump. Voters were drawn to him for lots of reasons, but being dogmatic was NOT one of them.
The leaders of Europe and Canada would need to take the hard political decisions to boost defense spending, he said.
"Every administration tries to improve relations, but there is a very basic fundamental fact: Across the geopolitical chessboard the US and Russian Federation have fundamentally very different interests", said Harry Kazianis, a senior fellow for defense policy at the Center for the National Interest, a Washington think tank advocating "realistic" foreign policy.
One of Donald Trump's many memorable lines on the campaign trail was about ISIS.
Tensions have recently flared over Moscow's military backing of Syrian President Bashar al-Assad, whom the USA accused of using chemical weapons last week.
For more than a year, Trump has said NATO is outdated and costing the USA too much money, suggesting replacing it with an alternative organisation focused on counter-terrorism and repeatedly using the word "obsolete".
On Monday, Trump signed off on the Balkan country of Montenegro becoming NATO's newest member, a move that Moscow has long opposed.
"For Russia, this is something they did not want to see happen", NATO Supreme Allied Commander Europe, Gen. Curtis Scaparrotti, told the House Armed Services Committee last month.