Trump calls Trudeau 'two-faced' after hot mic catches NATO leaders speaking candidly

President Donald Trump blasted Canadian Prime Minister Justin Trudeau as "two-faced" on Wednesday after Trudeau was caught on an open mic with other world leaders discussing the NATO summit in London and making what may have been references to Trump.

The video, which quickly went viral online, showed Trudeau, British Prime Minister Boris Johnson, French President Emmanuel Macron, and others speaking at a Buckingham Palace reception. The video begins with Johnson looking toward Macron and asking, "Is that why — is that why you were late?"

Trudeau jumped in, "He was late because he takes a 40 minute — 40 minute press conference off the top."

After a cut in the footage, Trudeau adds, "I watched his team's jaws drop on the floor."

NBC News had not confirmed whom Trudeau was speaking about, although earlier in the day, Trump was involved in a 38-minute press event alongside Macron. Prior to that, the president spoke alongside NATO Sec. Gen. Jens Stoltenberg for about 53 minutes.

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Macron and Johnson's offices declined to comment on the video, and Canadian officials were not immediately available for a response.

'Well, he's two-faced," Trump said of Trudeau alongside German Chancellor Angela Merkel on Wednesday. "And honestly with Trudeau he's a nice guy, but the truth is I called him out on the fact he's not paying 2 percent (in funding NATO) and I guess he's not happy about it."

Related: Trump in London for NATO summit

It's not the first time Trump has taken aim at his Canadian counterpart, calling Trudeau "very dishonest and weak" after a Group of Seven summit in Canada last year.

The world leaders' overheard conversation took place at the end of whirlwind day in which Trump spent more than two hours speaking to reporters in sessions alongside the likes of Macron, Stoltenberg and Trudeau.

Trump earlier in the day criticized Macron for saying NATO was experiencing a "brain death," saying the remark was "very, very nasty" and "insulting," bashing his French counterpart's handling of the French economy. Then, while sitting alongside Macron, Trump jokingly asked if the French leader would "like some nice ISIS fighters?"

"I could give them to you," Trump said. "You could take every one you want."

"Let's be serious," Macron said, adding that the fight against ISIS is "not yet done."

"I'm sorry to say that," Macron said.