Top Hegseth advisor Dan Caldwell placed on administrative leave by Defense Department

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A top advisor to Defense Secretary Pete Hegseth was escorted out of the Pentagon on Tuesday and placed on administrative leave, according to a Defense Department official. 

Reuters first reported Caldwell had been placed on leave for an "unauthorized disclosure" of information amid an investigation into Pentagon leaks. An official confirmed to Fox News Digital that Reuters' reporting is accurate but declined to comment on an ongoing investigation. 

Caldwell previously worked at restraint-minded think tank Defense Priorities and Concerned Veterans for America, a group formerly led by Hegseth. A foreign policy realist, he has argued that the U.S. should dramatically reduce its footprint in Europe and pull out forces in Iraq and Syria. 

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US Secretary of Defense Pete Hegseth's top adviser Dan Caldwell has been placed on administrative leave  (FRANCO BRANA/AFP via Getty Images)

Last month, the Defense Department announced a probe into "recent unauthorized disclosures of national security information" and said it planned to use polygraphs to determine the source of leaks. 

"The use of polygraphs in the execution of this investigation will be in accordance with applicable law and policy," DOD Chief of Staff Joe Kasper wrote in a memo. "This investigation will commence immediately and culminate in a report to the Secretary of Defense."

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He wrote that "information identifying a party responsible for an unauthorized disclosure" would be referred for criminal prosecution.

Caldwell did not immediately reply to a request for comment. 

Caldwell's closeness to the defense secretary was underscored in the unintentionally leaked Signal chat on Houthi strikes, where Hegseth named him as the Pentagon point of contact for the offensive campaign.