U.S. President Donald Trump has admitted to making up information in a meeting with Justin Trudeau, telling the Prime Minister the U.S. has a trade deficit with Canada even though he had no idea if that was true.

Mr. Trump then went on to claim that he subsequently discovered he was correct, and the U.S. indeed has a “$17-billion” deficit with its neighbour to the north. He also suggested, inexplicably, that the U.S. does not include either energy or timber in its calculations of the figure.

It all came in a rambling anecdote, told by the President at the end of a fundraising speech Wednesday, a tape of which was leaked to the Washington Post.

While the President is known for frequently making false claims, it is unusual for him to openly admit to it.

On Thursday, Mr. Trump doubled down on his trade deficit claim on Twitter.

“We do have a Trade Deficit with Canada, as we do with almost all countries (some of them massive). P.M. Justin Trudeau of Canada, a very good guy, doesn’t like saying that Canada has a Surplus vs. the U.S.(negotiating), but they do…they almost all do…and that’s how I know!” Mr. Trump tweeted.

At issue is the balance of trade, the difference between how much in goods and services a country imports and exports. Mr. Trump believes the U.S.’s US$566-billion trade deficit is a sign that his country is being cheated by its trading partners, a view not widely shared by economists.

The Office of the United States Trade Representative shows the U.S. with a trade surplus over Canada, calculating it at US$12.5-billion. According to the USTR, Canada runs a surplus in the trade of goods of US$12.1-billion, but the U.S. more than makes up for it with a US$24.6-billion surplus in services.

The U.S., Canada and Mexico are renegotiating the North American free-trade agreement at Mr. Trump’s behest, as he seeks to tip the balance of trade in the U.S.’s favour.

In the Wednesday speech, at a private St. Louis fundraiser for Missouri senate candidate Josh Hawley, Mr. Trump expounded on his dislike of the media and boasted about landing a meeting with North Korean dictator Kim Jong-un before turning his attention to Canada.

“Trudeau came to see me. He’s a good guy, Justin. He said ‘No, no, we have no trade deficit with you. We have none. Donald, please.’ Nice guy, good-looking, comes in ‘Donald, we have no trade deficit.’ He was very proud, because everybody else, you know, we’re getting killed,” the newspaper quoted Mr. Trump as saying, performing an impression of Mr. Trudeau. “I said ‘Wrong, Justin, you do.’ I didn’t even know. Josh, I had no idea. I just said ‘You’re wrong.’ You know why? Because we’re so stupid. And I thought they were smart. I said ‘You’re wrong, Justin.’”

Mr. Trump said he almost conceded the point to Mr. Trudeau, but had one of his aides and one of Mr. Trudeau’s people check the numbers.

“He said ‘Nope, we have no trade deficit.’ I said ‘Well, in that case, I feel differently.’ I said ‘But I don’t believe it,’ ” the President continued. “I sent one of our guys out. His guy, my guy, they went out. I said ‘Check, because I can’t believe it.’ ”

Mr. Trump went on to bizarrely claim that the U.S. only appears to not have a trade deficit with Canada because it does not count energy or timber. It was not clear why the President thought this: Oil is a major Canadian export to the U.S., and the two countries are currently locked in a trade dispute over Canadian exports of softwood lumber, but both goods are counted in trade balance calculations.

“’Well, sir, you’re actually right. We have no deficit, but that doesn’t include energy and timber. But when you do, we lose $17-billion a year,’” Mr. Trump quoted his aides as telling him. “It’s incredible.”

Mr. Trump also expressed some grudging admiration for Canada’s toughness at the negotiating table, where Ottawa is fighting back against a string of protectionist demands from Mr. Trump, including forcing all vehicles made in Canada to contain 50 per cent U.S. content, and restricting Canadian companies from bidding on U.S. government contracts.

“By the way, Canada, they negotiate tougher than Mexico,” Mr. Trump said.

Prime Minister Justin Trudeau, who is currently on vacation in Florida, did not comment on Mr. Trump’s remarks Thursday. His office directed all questions to Foreign Affairs Minister Chrystia Freeland, who pointed to the U.S. government’s own statistics on the trade surplus with Canada.

“Canada and the United States have a balanced and mutually beneficial trading relationship. According to their own statistics, the U.S. runs a trade surplus with Canada,” said Ms. Freeland’s spokesperson Adam Austen.

Mr. Austen added that Canada is “energetically” working toward modernizing and updating NAFTA to support good jobs and the middle class in Canada, the U.S. and Mexico.

The Wednesday speech was not the first time Mr. Trump has recounted sparring over the trade deficit with Mr. Trudeau: At a December rally in Pensacola, Florida, he told a similar story with the same numbers. On that occasion, however, he left out the admission that he had made up the existence of the deficit on the spot.