WASHINGTON — President Trump lashed out at John Brennan on Saturday in the latest effort to counter criticism of his decision to revoke the former CIA director’s security clearance.

Trump said in a Twitter post Saturday that Brennan “will go down as easily the WORST” CIA director in history and called him “a loudmouth, partisan, political hack who cannot be trusted with the secrets to our country!”

The president also suggested that unspecified “mistakes” Brennan made while serving as CIA director should be “looked at.”

Trump’s comments came after days of criticism from former U.S. national security officials and military leaders who cast Trump’s cancellation of Brennan’s clearance – apparent retaliation for his criticism of the president – as a dangerous precedent.

A joint letter from more than a dozen former senior intelligence officials who served Republican and Democratic administrations said Trump’s decision “has nothing to do with who should and should not hold security clearances – and everything to do with an attempt to stifle free speech.”

That letter followed an op-ed article published in The Washington Post from the retired admiral who oversaw the capture of Osama bin Laden. The retired special operations commander, William H. McRaven, called Brennan “one of the finest public servants I have ever known” and challenged Trump to revoke his security clearance, too.

Before being appointed CIA director by President Barack Obama, Brennan, 62, spent 25 years at the agency, including a stint as the station chief in Saudi Arabia. He was also director of the National Counterterrorism Center.

McRaven said Brennan’s “honesty and character have never been in question, except by those who don’t know him.”

Brennan said on MSNBC Friday that Trump is “drunk with power,” and criticized Republicans in Congress for turning a blind eye to the his actions.