EXCLUSIVE: The Biden-Harris administration has again blocked a request by Fox News to reveal the nationalities of people on the FBI terror watchlist arrested at the border by Border Patrol, citing the privacy interests of those who were encountered and arguing that it could expose law enforcement “vulnerabilities” and “tip off” terrorists.

“[Customs and Border Protection (CBP)] is committed to protecting the identity of individuals and avoiding divulging information about any individual by either direct or indirect means,” the agency said in a letter to Fox. “Releasing data for a particular nationality, or nationalities, that reflect a small number of individuals could lead to identification, especially by organizations familiar with the individuals.”

Fox’s Bill Melugin filed a Freedom of Information Act request in October 2023 seeking the nationalities of suspects on the FBI terror watchlist arrested at the southern border entering between ports of entry by Border Patrol.

The request sought only the nationalities of those encountered, not the names or dates of birth or any other identifying information.

BIDEN ADMIN REFUSES TO REVEAL TERROR WATCHLIST NATIONALITIES AS ILLEGAL IMMIGRATION EXPLODES ON HIS WATCH 

In May, CBP told Fox it would not provide the information, although it acknowledged the information is maintained in the Terrorist Screening Dataset (TSDS). 

The letter said then that it was applying exemptions to protect the disclosure of files that may create a “clearly unwarranted invasion of personal privacy” and must balance a public’s right to disclosure against an individual’s right to privacy.

In its letter to Fox this month, the agency doubled down on that reasoning.

FEDERAL JUDGE BLOCKS BIDEN ADMIN MOVE TO GIVE LEGAL STATUS TO ILLEGAL IMMIGRANT SPOUSES OF US CITIZENS

“The privacy interests of third parties (being protected from public disclosure because they could conceivably be subject to harassment and annoyance in his/her private life) far outweigh whatever public interest, if any, exists in having their information released.”

The agency also claimed that the release of the information would reveal investigative techniques used in processing and apprehending terrorists.

“By providing this information, it could allow targets to alter their behavior to avoid detection and exploit the gaps in CBP’s law enforcement intelligence, as well as compromise national security. Additionally, providing the requested information could disclose terrorist travel trends by geographic area which could help tip off terrorists about the government’s knowledge of travel plans, allowing the terrorists to take countermeasures against the investigators and their investigations,” it says.

It gave the examples of allowing terror groups to compare disclosed nationalities to operational numbers. 

“If such an organization were to move ‘X’ number of operatives of one nationality over the relevant period, and the disclosed nationality numbers were substantially lower than X, the terrorist organization could infer a large percentage of its operatives from a particular nationality have been able to move undetected (thereby minimizing the deterrent effect of the TSDS),” the letter said.

The agency argued that the disclosure of nationalities could allow bad actors “to undertake countermeasures to avoid CBP’s law enforcement activities and exploit any vulnerabilities in CBP’s law enforcement efforts.”

CLICK HERE FOR MORE COVERAGE OF THE BORDER SECURITY CRISIS

“This information could allow bad actors to reverse engineer effective countermeasures to facilitate undetected movement and activity and thwart CBP interdiction efforts,” it argued.

There were 172 encounters of nationals on the terror watchlist at the border between ports of entry last fiscal year and more than 560 at the ports of entry.

So far this fiscal year, there have been 98 encounters between the ports of entry and 324 at the ports.

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The watchlist, now called the Terrorist Screening Dataset, includes known or suspected terrorists, as well as additional individuals believed to pose a potential threat to the U.S. — including affiliates of individuals on the watchlist.