WASHINGTON–John McCain is the latest high-profile politician to repeat the diehard American falsehood that the 9/11 terrorists entered the United States through Canada.

Just days after Janet Napolitano, the U.S. homeland security secretary, sparked a diplomatic kerfuffle by suggesting the terrorists took a Canadian route to the U.S. eight years ago, McCain defended her by saying that, in fact, the former Arizona governor was correct.

"Well, some of the 9/11 hijackers did come through Canada, as you know," McCain, last year's Republican presidential candidate, said on Fox News on Friday.

The Arizona senator's remarks prompted the Canadian embassy to immediately reissue remarks made earlier this week by Ambassador Michael Wilson, who reminded Americans once again that no 9/11 perpetrators came to the U.S. via Canada.

"Unfortunately, misconceptions arise on something as fundamental as where the 9/11 terrorists came from," Wilson said.

"As the 9/11 Commission reported in July 2004, all of the 9/11 terrorists arrived in the U.S. from outside North America. They flew to major U.S. airports. They entered the U.S. with documents issued to them by the U.S. government. No 9/11 terrorists came from Canada."

Crestfallen embassy officials contacted McCain's office soon after his Fox News remarks to set the record straight. McCain, an avid supporter of NAFTA and a powerful friend to Canada on Capitol Hill, recently visited the Canadian Embassy and had lunch with Wilson.

The normally reserved Wilson made his 9/11 remarks on Tuesday following a CBC interview in which Napolitano appeared to believe that the hijackers entered the U.S. from Canada.

She later said she had misunderstood a question asked during the interview and was well aware there had been no Canadian 9/11 connection, but added that the Canada-U.S. border had, in the past, posed a security risk to Americans.

The next day, Napolitano appeared at a border conference and suggested Canada was more lax in its immigration policies than the U.S., alleging Canadian authorities allow people into the country that would not pass muster south of the border.

Napolitano has also ruffled diplomatic feathers with her insistence that the Canadian border must not be treated any differently than the U.S.-Mexican boundary, where a drug war rages and countless illegal immigrants flood into America every year.

McCain expressed some sympathy for Canada on that front on Friday.

"The difference, obviously, is, with all due respect to the Mexicans, there's not corruption on our northern border," he told Fox News. "And, unfortunately, there is significant corruption, great corruption and drug cartels on our southern border."

In Washington for G7 and G20 meetings on Friday, Canada's finance minister expressed frustration that the Canada 9/11 myth lives on.

"It's unfortunate that what is a statement that is not true is being repeated from time to time," Jim Flaherty said. "It's just factually wrong ... I would hope that people wouldn't want to make statements that are inaccurate so that we won't hear much of that anymore."