National Security Council official Lt. Col. Alexander Vindman is defending himself from a Fox News guest accusing him of “espionage.”

On Wednesday, Vindman lawyer David Pressman sent a letter to Fox News that requests a retraction or correction of a “a deeply flawed and erroneous” segment on Fox News host Laura Ingraham’s show last month that featured former Justice Department official John Yoo.

Soon after Vindman’s prepared remarks in his closed-door impeachment deposition were released on October 28, Yoo accused Vindman “espionage” on Ingraham’s show. After Ingraham called attention to the “buried” detail in a New York Times report that “Ukrainian officials sought advice” from Vindman “about how to deal with Giuliani” due to his fluency in both Ukrainian and Russian, Yoo said that he found the detail “astounding” and that “some people might call that espionage.”

Earlier this month, Yoo wrote in an opinion piece in USA Today that he “didn’t call Alexander Vindman a spy,” but that Ukraine engaged in espionage.

Fox News said in a statement that Yoo was “responsible for his own sentiments and he has subsequently done interviews to clarify what he meant.”

Pressman wrote that the segment “sparked a torrent of republications and copycat false charges” and that Vindman “had never in his decorated 20-year career of service to his country been accused of having dual loyalties or committing espionage.”

Pressman added that the segment “created a false factual basis to render sinister otherwise innocuous facts” and has forced Vindman and his family to “ensure their physical security in the face of threats.”

“LTC Vindman and his family have been forced to examine options, including potentially moving onto a military base, in order to ensure their physical security in the face of threats rooted in the falsehood that Fox News originated,” Pressman wrote in the letter.

Pressman then urged Fox News to “take steps to ensure that it does not publish further defamatory falsehoods concerning LTC Vindman.”

“Fox News has a responsibility to help put out the fire it lit when it falsely accused a decorated soldier of disloyalty to his country,” Pressman wrote in the letter. “Vindman, who has dedicated his life to defending America out of the public eye, deserves better than to be falsely attacked when compelled by law and duty to speak the truth.”

Read the letter below: