Trump and Trudeau / REUTERS

Donald Trump has reacted furiously to footage of world leaders apparently making fun of him, calling Justin Trudeau "two-faced" then cancelling a press conference and cutting short his attendance at a NATO summit.

The U.S. president was asked whether he had seen the clip in which his international counterparts appeared to joke about his explosive press conference with Emmanuel Macron, and his erratic diplomatic style, at Tuesday night's Buckingham Palace reception, The Independent reported.

"You just watched his team's jaws drop to the floor!" Mr Trudeau apparently said of Mr Trump while speaking with Boris Johnson, Mr Macron and Princess Anne.

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"Well, he's two-faced," Mr Trump said of the Canadian prime minister when questioned on Wednesday afternoon, and suggested the unguarded comments were based in frustration at U.S. demands that Canada contribute more to NATO.

Speaking alongside Angela Merkel on Wednesday, Mr Trump added: "Honestly, with Trudeau he's a nice guy, I find him to be a very nice guy.

"But you know the truth is that I called him out on the fact that he's not paying 2 per cent, and I guess he's not very happy about it."

Mr Trump continued: "He's not paying 2 per cent and he should be paying 2 per cent. It's Canada, they have money and they should be paying 2 per cent, so I called him out on that and I'm sure he wasn't happy about it but that's the way it is.

"Look, I'm representing the U.S. and he should be paying more than he's paying, and he understands it."