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A new CIA document reportedly states that bizarre illnesses being attributed to "Havana Syndrome" are not the results of an attack by a foreign power, but those findings are being challenged by a whistleblower who claims the agency is hiding something.

An NBC News report late Wednesday night citing "six people briefed on the matter" said that, according to an interim report by the CIA, hundreds of supposed Havana Syndrome cases could plausibly be attributed to other things, even though roughly two dozen remain unexplained.

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"CIA interim report is disinformation," countered national security attorney Mark Zaid. "Other agencies furious no coordination occurred & they disagree."

Zaid's comment is in line with what one source told NBC about how the CIA acted alone in putting together the interim report and did not consult with the Department of Defense or other government agencies.

Zaid said a whistleblower complaint has been filed challenging the CIA report.

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"This interim report is largely bc CIA is having revolt within its workforce as officers don't want to go overseas," Zaid added.

Havana Syndrome refers to brain injuries of unknown origin, marked by symptoms including headaches, memory and cognition problems, hearing and vision loss, and dizziness. It was first reported in 2016 by 26 diplomats and their families working in Cuba. Since then, more than 200 cases have been reported, including a member of CIA Director Bill Burns’ team who claimed to suffer symptoms on a trip to India.

The New York Times reported that despite the interim report's findings, the CIA is still investigating two dozen unexplained cases, and Burns said, "We are not done."

Former CIA officer Marc Polymeropoulos, who suffered Havana Syndrome symptoms, noted that an investigation could take time.

"It took us 10 years to find Osama bin Laden," Polymeropoulos told the Times. "I would just urge patience and continued investigation by the intelligence community and the Department of Defense."

In November, the FBI deemed Havana Syndrome to be a "top priority."

The CIA launched a task force in December to investigate the cause of Havana Syndrome after scientists for the National Academies of Sciences, Engineering, and Medicine identified "directed, pulsed radio frequency (RF) energy" as the most likely cause of the mysterious condition. 

Zaid's law firm is also handling a Freedom of Information Act lawsuit against the Department of Defense seeking information related to Havana Syndrome and a 2014 memo the National Security Agency provided to former NSA employee Michael Beck. The lawsuit states that Beck, while working for the NSA in 1996, had been working in an unidentified "hostile foreign country," and in 2006 he was diagnosed with young-onset Parkinson's Disease. The complaint states that a colleague of Beck's who was in the same country with him also developed the same illness and later died.

The FOIA complaint states that both Beck and his colleague "were exposed to some form of energy, possibly microwave in nature, that caused the Parkinson Disease to develop." In 2014, it says, the NSA gave Beck "a carefully worded" memo that acknowledged "intelligence information from 2012 associating the hostile country to which Mr. Beck traveled to in the late 1990s with a high-powered microwave system weapon that may of the ability to weaken, intimidate, or kill an enemy over time and without leaving evidence."

That memo allegedly stated that, according to the 2012 intelligence, "this weapon is designed to bathe a target’s living quarters in microwaves, causing numerous physical effects, including a damaged nervous system."

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The NSA told Beck that they did not have evidence that such a weapon was used on Beck, the complaint says.

The lawsuit was filed by the James Madison Project and investigative reporter Brian Karem after a FOIA request for information about the intelligence behind the memo was denied. The DoD declined to comment on the ongoing litigation, referring Fox News to the Justice Department, which did not immediately respond.

Fox News' Jennifer Griffin and Caitlin McFall contributed to this report.