Washington (CNN) Former CIA Director John Brennan is hitting back at President Donald Trump in a blistering New York Times op-ed after his security clearance was revoked Wednesday.

"Mr. Trump clearly has become more desperate to protect himself and those close to him, which is why he made the politically motivated decision to revoke my security clearance in an attempt to scare into silence others who might dare to challenge him," Brennan wrote in the op-ed published Thursday morning.

He argued that Trump's "claims of no collusion are, in a word, hogwash."

Trump announced Wednesday that he decided to revoke Brennan's security clearance, marking an unprecedented use of a president's authority over the classification system to strike back at one of his prominent critics.

"Mr. Brennan's lying and recent conduct characterized by increasingly frenzied commentary is wholly inconsistent with access to the nation's most closely held secrets," Trump said in a statement relayed by White House press secretary Sarah Sanders.

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