THE HAGUE, Netherlands (AP) — President Donald Trump on Wednesday is meeting with members of a NATO alliance that he has worked to bend to his will over the years and whose members are rattled by his latest comments casting doubt on the U.S. commitment to its mutual defense guarantees.

Trump’s comments en route to the Netherlands that his fidelity to Article 5 “depends on your definition” are drawing attention at the NATO summit, as will the new and fragile Iran-Israel ceasefire that Trump helped broker after the U.S. unloaded airstrikes on Iran’s nuclear facilities.

At the same time, the alliance is poised to enact one of Trump’s chief priorities for NATO: a pledge by its member countries to increase, sometimes significantly, how much they spend on their defense.

“I’ve been asking them to go up to 5% for a number of years,” Trump said Wednesday morning as he met with Mark Rutte, the alliance’s secretary-general. “I think that’s going to be very big news.”

The boost in spending follows years of Trump complaints that other countries weren’t paying their fair share for membership in an alliance created as a bulwark against threats from the former Soviet Union. Most NATO countries, with the key exception of Spain, are preparing to endorse the 5% pledge, motivated to bolster their own defenses not just by Russian President Vladimir Putin’s invasion of Ukraine but also, perhaps, to placate Trump.

As a candidate in 2016, Trump suggested that he as president would not necessarily heed the alliance’s mutual defense guarantees outlined in Article 5 of the NATO treaty. In March of this year, he expressed uncertainty that NATO would come to the United States’ defense if needed, though the alliance did just that after the Sept. 11, 2001, attacks.

On Tuesday, he told reporters aboard Air Force One on his way to The Hague for the summit that whether he is committed to Article 5 “depends on your definition.”

“There’s numerous definitions of Article 5. You know that, right?” Trump said. “But I’m committed to being their friends.” He signaled that he would give a more precise definition of what Article 5 means to him once he is at the summit.

New Hampshire Sen. Jeanne Shaheen, the top Democrat on the Foreign Relations Committee who traveled to The Hague and met with several foreign leaders at the summit, said other countries raised “understandable questions” about the U.S.’s commitment to the alliance, “certainly given President Trump’s past statements.”

“We were very strong and reassuring everyone that we are committed to NATO, we are committed to Article 5, we are committed to maintaining troops on the eastern flank,” said Shaheen, who represented the U.S. Senate with Democratic Sen. Chris Coons of Delaware.

Trump also vented to reporters before leaving Washington about the actions by Israel and Iran after his announced ceasefire — although on Monday, he said the ceasefire was “very good.”

After Trump arrived in the Netherlands, news outlets, including The Associated Press, published stories revealing that a U.S. intelligence report suggested in an early assessment that Iran’s nuclear program had been set back only a few months by weekend strikes and was not “completely and fully obliterated,” as Trump had said.

But on Wednesday morning, Trump and other senior Cabinet officials vigorously pushed back on the assessment and Defense Secretary Pete Hegseth said the administration was launching an investigation into who disclosed those findings to reporters.

“That hit ended the war,” Trump said. Drawing comparisons to the atomic bombings from the U.S. during World War II, he added: “I don’t want to use an example of Hiroshima. I don’t want to use an example of Nagasaki. But that was essentially the same thing. That ended that war.”

The White House has not said what other world leaders Trump would meet with one-on-one while in The Hague, but Trump said in his morning meeting with Rutte that he will meet with Ukrainian President Volodymr Zelenskyy later Wednesday.