Carlson had claimed in June that the NSA was spying on the electronic communications of his show in order to leak them in an attempt to take his show off the air. The Fox News host said at the time that a "whistleblower within the US government" reached out to warn him about the monitoring.
While Carlson, known for spreading conspiracy theories, admitted that he would usually be "skeptical" of such a "shocking claim," he said that the whistleblower knew information about a story Carlson was working on that he says could have only come from his texts and emails. "There's no other possible source for that information, period," said Carlson at the time.
The NSA issued an official statement at the time denying Carlson's claims, calling them "untrue."
Carlson rejected the NSA's denial, calling it an "infuriatingly dishonest formal statement" and "an entire paragraph of lies," adding that the NSA did not explicitly deny his claim that it read his emails. The Fox News host also stated that the Biden administration did not explicitly deny the claims.
Two people familiar with the matter told The Record that the NSA had conducted an examination and found that Carlson's communications were not targeted or intercepted. The review was shared with both the House and Senate Intelligence committees.
The agency found that Carlson had been mentioned in communications between third parties and his name was then revealed through "unmasking," in which relevant government officials can request the identities of American citizens in intelligence reports to be divulged, as long as there is an official reason, according to the sources.
The Record's sources declined to name who mentioned Carlson.
A Fox News spokesman expressed outrage at the report, telling The Record, "For the NSA to unmask Tucker Carlson or any journalist attempting to secure a newsworthy interview is entirely unacceptable and raises serious questions about their activities as well as their original denial, which was wildly misleading."
Earlier this month, Axios reported that Carlson was talking to US-based Kremlin intermediaries in order to set up an interview with Russian President Vladimir Putin shortly before he made the accusations against the NSA.
Sources told Axios that US government officials learned about Carlson's efforts to get the interview and Carlson subsequently learned that the government was aware. The Axios report stressed that while the NSA denied targeting Carlson, it never categorically denied that Carlson's communications were incidentally collected.
Axios provided three possible explanations for why Carlson's communications could have been collected. The first scenario involved the US government submitting a request to the Foreign Intelligence Surveillance Court in order to monitor the Fox News host to protect national security, although the report stressed that this was the least likely scenario.
A second possible scenario is that one of the Kremlin intermediaries was under surveillance as a foreign agent, although Carlson's identity would have been masked in intelligence reports and it's unclear how a US official could justify unmasking his identity.
A third scenario may not even have involved Carlson's communications. Instead, the US government may have been monitoring the communications of people connected to Putin and may have intercepted communications discussing Carlson's request for an interview. In this scenario as well, Carlson's identity would have been masked, according to Axios.
A former government official told The Record that Carlson may have learned that his attempts to gain an interview had been involved in intelligence reports through FBI officials who may have offered Carlson a "defensive briefing," where he would be warned that he was the target in a potential intelligence influence operation by foreign adversaries.
While the FBI wouldn't have revealed any details about how the information was obtained, Carlson may have concluded that he was being spied on, subsequently building his claim.
The official added that a second possibility is that there is a leak in the national security apparatus and the information in the NSA report was illegally disclosed to Carlson.
In 2013, former NSA contractor Edward Snowden exposed the NSA for collecting the phone records of millions of American citizens and for data-mining the servers of internet companies, such as Google, Facebook and Apple.
Carlson's claims came just weeks after the US Department of Justice said that it would no longer seek source information from reporters in leak investigations after revelations that former president Donald Trump's administration had secretly obtained phone and email records from a number of journalists.
CNN and the Washington Post have said the Trump administration had secretly tried to obtain the phone records of some of their reporters over work they did in 2017.
The New York Times reported that the Justice Department under presidents Trump and Joe Biden waged "a secret legal battle to obtain the email logs of four New York Times reporters," and imposed a gag order on executives.
In May, Biden said he would not allow his Justice Department to seize the phone or email records of reporters, saying any such move would be "simply wrong."
In a statement, the White House said that issuing subpoenas for reporters' records in leak investigations is not consistent with Biden administration policy.
Reuters contributed to this report.