Arizona Senator John McCain, seen with Homeland Security Secretary Janet Napolitano in January, told Fox News on Friday that some of the 9/11 hijackers did come through Canada. (Kevin Wolf/Associated Press)

Arizona Senator John McCain is the latest high-profile politician to repeat the diehard American falsehood that the Sept. 11, 2001, attackers entered the United States through Canada.

Just days after Janet Napolitano, the U.S. homeland security secretary, sparked a diplomatic kerfuffle by suggesting the perpetrators 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 Tuesday by Ambassador Michael Wilson, who reminded Americans once again that none of the attackers 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."

Canadian embassy officials were also in touch with McCain's office to set the record straight. McCain recently visited the Canadian Embassy and had lunch with Wilson.

CBC interview with Napolitano

The normally reserved Wilson made his 9/11 remarks on Tuesday, a day after Napolitano suggested to the CBC's Neil Macdonald in a televised interview 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."