"I find him to be a very nice guy, but the truth is I called him out on the fact that he's not paying two per cent and I guess he's not happy about it".
Trudeau had a quiet word and a handshake with Trump as he arrived at the summit Wednesday, and later tried to shrug off the episode. His return to Washington, DC, comes in the middle of another public House Judiciary Committee impeachment hearing.
Trump did not take kindly to Trudeau's comments. Picture: AP Photo/Frank Augstein. Picture: Host Broadcaster via AP.
That included an exchange with Trump during an impromptu 40-minute news conference Tuesday in which the Canadian prime minister tried to deflect the US president's attention away from the fact Canada has no plan to reach the two-per-cent target.
The reception footage also shows Trudeau talking about "his team's jaws drop to the floor", though the subject isn't clear.
The leaders do not use Trump's name, but the US president took dozens of questions from journalists on Tuesday during impromptu news conferences at the start of his individual meetings with Macron, Trudeau and NATO Secretary-General Jens Stoltenberg.
"We have unfortunately a large number that haven't met the goal", Trump said of other leaders at the summit. "[France] have a very high unemployment rate".
The NATO Summit just turned into "Melrose Place".
The pair later spoke to the press together.
Johnson, meanwhile, professed ignorance when asked by reporters about the conversation.
"I really don't know what is being referred to there".
A huddle which included Prime Minister Boris Johnson and the Princess Royal was filmed apparently gossiping about the USA president's unorthodox style on Tuesday night, although Mr Trump is not mentioned by name.
As he did at last year's North Atlantic Treaty Organisation meeting, Trump threw out normal summit protocol and used his one-on-one appearances with allied leaders to field dozens of questions from the world's media.
Soon after it posted on Twitter, the video went viral. Picture: AAP Image/Mick Tsikas.
As the 70th anniversary concluded the alliance reaffirmed the unity of the intergovernmental military organization.
Trudeau, who leads the center-left Liberal Party in Canada, was recently endorsed in a tough reelection campaign by Trump's predecessor, former President Barack Obama. Prince Harry and Meghan were also absent while on a six-week hiatus in the US.
"This is why he's a great politician, because that's one of the greatest non-answers I've ever heard. Our commitment to article 5, the collective defence clause of our alliance, is iron-clad".