Story highlights Trump attended NATO meetings Thursday

He delivered the remarks in front NATO members

Brussels (CNN) President Donald Trump on Thursday chided NATO member countries directly for not meeting their financial commitments to the alliance and declined to reiterate US commitment to the alliance's mutual defense pledge.

"Members of the alliance must finally contribute their fair share and meet their financial obligations," Trump told the heads of state, who stood silently -- some shifting uncomfortably -- behind him.

"Twenty-three of the 28 member nations are still not paying what they should be paying and what they are supposed to be paying for their defense. This is not fair to the people and taxpayers of the United States," he said.

The call appeared to reveal Trump's continued misunderstanding of NATO members' defense commitments. While Trump argued that many of the allies "owe massive amounts of money from past years," the 2% defense spending benchmark that allies must meet is designed to boost their military, not to funnel money to NATO or other allies.

Trump's remarks -- paired with his conspicuous decision not to reiterate US commitment to NATO's mutual defense provision, Article 5 -- are likely to unsettle allies who had hoped to hear Trump assuage their concerns about his commitment to the historic alliance.

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