WASHINGTON — White House Press Secretary Sarah Sanders said Friday that Customs and Border Protection picked up nearly 4,000 known or suspected terrorists last year "that came across our southern border."

But in fact, the figure she seems to be citing is based on 2017 data, not 2018, and refers to stops made by Department of Homeland Security across the globe, mainly at airports.

In fiscal 2017, the latest year for which data is available, according to agency data and the White House's own briefing sheet, the Department of Homeland Security prevented nearly 4,000 known or suspected terrorists from "traveling to or entering the United States."

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According to Justice Department public records and two former counterterrorism officials, no immigrant has been arrested at the southwest border on terrorism charges in recent years.

White House spokeswoman Sarah Sanders leaves after speaking to the press outside the White House on Jan. 4, 2019. Jim Young / Reuters

The White House did not respond to a request for comment about Sanders' statement.

Ahead of President Donald Trump's meeting Friday afternoon with Congressional leaders to negotiate the end of the government shutdown, the White House issued briefing materials that stated "3,775 known or suspected terrorists [were] prevented from traveling or entering the U.S. by DHS" in fiscal year 2017. Nowhere did the briefing materials state the known or suspected terrorists were stopped at the southern border.

Ned Price, who served on President Barack Obama's National Security Council, said many of those 3,775 were stopped simply because their name matches that of someone on a terrorist watch list, which have grown in recent years, and not because they pose a threat.

"So-called terrorist watchlists are an important tool in our national security arsenal, but they are far from fool-proof in large part because of their sheer size. The number of people on such lists ballooned in the years after 9/11, with some reports indicating that more than one million names had been associated with suspected terrorist activity. That's why false-positives, including in the case of crossings at our southern border, are commonplace. Even the late Ted Kennedy was registered on one such list when attempting to fly, presumably because of the commonality of his name," Price said.

Nick Rasmussen, the former director of the National Counterterrorism Center from December 2014 through December 2017 said, "During my tenure, the threat of terrorists trying to infiltrate the United States across our southern border was much more of a theoretical vulnerability than an actual one. It simply isn’t the case that terrorist groups like ISIS and al Qaeda see the southern border as the optimal the way to get would-be terrorists into the country."

DHS Secretary Kirstjen Nielsen said at a press conference at the White House Friday afternoon that more than 3,000 immigrants have been stopped at the southwest border, over an unspecified period, because they are special interest aliens. DHS classifies nearly all immigrants crossing the border who is a national of a country outside of the Western Hemisphere as a Special Interest Alien, according to DHS reports.

A spokeswoman for the National Counterterrorism Center did not respond to a request for comment.