The White House announced Wednesday that President Donald Trump is revoking the security clearance of former Central Intelligence Agency Director John Brennan, who has been a harsh critic of Trump’s rhetoric and policies.

“Historically, former heads of intelligence and law enforcement agencies have been allowed to retain access to classified information after their government service, so that they can consult with their successors regarding matters about which they may have special insights and as a professional courtesy. Neither of these justifications supports Mr. Brennan’s continued access to classified information,” Trump said in a statement read aloud by White House Press Secretary Sarah Huckabee Sanders at Wednesday’s press briefing.

“At this point in my administration, any benefits that senior officials might glean from consultations with Mr. Brennan are now outweighed by the risks posed by his erratic conduct and behavior,” the statement continued.

The announcement came after Brennan, who served as CIA director from 2013 to 2017, most recently criticized Trump for calling former White House aide Omarosa Manigault Newman a “dog” and a “crazed, crying lowlife.”

“It’s astounding how often you fail to live up to minimum standards of decency, civility, & probity. Seems like you will never understand what it means to be president, nor what it takes to be a good, decent, & honest person. So disheartening, so dangerous for our Nation,” Brennan said in a tweet about Trump on Tuesday.

Brennan responded to the revocation on Wednesday afternoon, calling it “part of a broader effort by Mr. Trump to suppress freedom of speech and punish critics.”

“It should gravely worry all Americans, including intelligence professionals, about the cost of speaking out,” Brennan said on Twitter. “My principles are worth far more than clearances. I will not relent.”

Trump said last month that he was considering revoking the security clearances of several former intelligence and national security officials who have criticized him, but had not yet taken such action. Republican House Speaker Paul Ryan had dismissed the threat as an example of Trump “trolling” his critics.

Sanders also said that Trump is reviewing the security clearances of several other former officials, all of whom have been critical of Trump, including former FBI Director James Comey, former Acting Attorney General Sally Yates, former Director of National Intelligence James Clapper, and former Deputy FBI Director Andrew McCabe.

“It’s unprecedented. I don’t know of a case where this has ever been done in the past,” Clapper said in a CNN interview after the announcement, adding that typically the CIA would handle decisions to revoke security clearances, rather than the White House or the President directly.

“Will the Republic stand or fall on whether John retains his access to classified information — or mine or any others that were named? Of course not,” Clapper told CNN. “The larger issue here, to me, throughout, has been infringement on First Amendment rights. And I think people ought to think seriously about that.”

When asked why the list included only former officials who have publicly criticized Trump, Sanders said, “if we deemed it necessary, we would certainly look into” others.

Get our Politics Newsletter. The headlines out of Washington never seem to slow. Subscribe to The D.C. Brief to make sense of what matters most. Please enter a valid email address. Sign Up Now Check the box if you do not wish to receive promotional offers via email from TIME. You can unsubscribe at any time. By signing up you are agreeing to our Terms of Use and Privacy Policy . This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply. Thank you! For your security, we've sent a confirmation email to the address you entered. Click the link to confirm your subscription and begin receiving our newsletters. If you don't get the confirmation within 10 minutes, please check your spam folder.

Write to Katie Reilly at Katie.Reilly@time.com.