WASHINGTON () President Donald Trump adopted a firm stance at the NATO leaders’ summit in the Netherlands on Wednesday, defending U.S. strikes on Iranian nuclear sites and urging allies to boost defense spending.

Trump praised the strength of the alliance but warned that if Iran rebuilds its nuclear program, the United States would strike again.

“This was a devastating attack, and it knocked them for a loop. And you know, if it didn’t, they wouldn’t have settled,” Trump told reporters.

Trump pushes for increased NATO defense spending

In addition to high-stakes talks on the Middle East, Ukrainian President Volodymyr Zelenskyy’s team has confirmed he will meet with Trump.

As part of Wednesday’s agenda, Trump could hold bilateral meetings with other leaders, likely to discuss the Israel-Iran war in more detail. A ceasefire between the two countries, though fragile, appeared to hold overnight.

Military spending is also a significant issue this year, and Trump has urged other NATO members to contribute at least 5% of their GDP to defense spending.

Spanish Prime Minister Pedro Sánchez has pushed back against that pledge, calling it “incompatible with our worldview.” Trump lashed out at the response, calling Spain “a low payer.”

Congress briefings on Iran postponed

Over the weekend, the U.S. conducted “Operation Midnight Hammer,” which struck three Iranian nuclear facilities — Fordow, Natanz, and Isfahan.

Trump called the attacks a “spectacular military success” and has since floated the idea of a regime change in Iran if the “current Iranian Regime is unable to MAKE IRAN GREAT AGAIN.”

Democrats on Capitol Hill have raised concerns about the strikes occurring without congressional approval, citing a lack of information and transparency from the Trump administration.

They’re also voicing outrage and demanding answers after the Trump administration postponed a pair of meetings to brief Congress on the war in the Middle East. Some want to know more about the exact damage to Iran’s nuclear program.

Trump’s team was confident the strikes had obliterated Iran’s facilities.