The officials, who served under both Republican and Democratic presidents, include former CIA Directors Michael Hayden, Leon Panetta, William Webster, Porter Goss, David Petraeus and George Tenet, several of the agency's former deputy directors and former Director of National Intelligence James Clapper.
High-ranking government officials sometimes retain security clearances after leaving office to advise their successors as needed, and some private sector companies can also require them.
Escalating Mr. Trump's tensions with the security establishment are the diverging views of the two sides on America's relations with Russia, and the alleged Russian interference to facilitate the President's victory in 2016.
"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", he said.
Trump on Wednesday openly tied his decision to strip Brennan of his clearance - and threaten almost a dozen other former and current officials - to the investigation into Russian election meddling and possible collusion with his campaign.
"He said explicitly that he did it because these people had a role back in the day leading the Russian Federation investigation - what he called the 'rigged witch hunt, '" Maddow said.
Brennan, who led the Central Intelligence Agency under Democratic President Barack Obama, on Thursday called Trump's denials "hogwash" and vowed not to be silenced. "And these people led it!" It remained up to Special Counsel Robert Mueller, who is leading the probe, to make a final conclusion, Clapper said.
Brennan is probably not a witness, Honig said, but someone like former Federal Bureau of Investigation director James Comey certainly isa "crucial witness".
Also on the list: fired FBI special agent Peter Strzok, who was removed from the Russian Federation investigation over anti-Trump text messages; former FBI lawyer Lisa Page, with whom Strzok exchanged messages; fired acting Attorney General Sally Yates; and senior Justice Department official Bruce Ohr. McRaven called Brennan "one of the finest public servants I have ever known".
"I'd also like to ask you to bring a major lawsuit against the drug companies on opioids", Trump told Sessions during a cabinet meeting on Thursday. "I think that they're very duplicitous".
Mr McRaven was the head of US Joint Special Operations Command from 2011 to 2014 and supervised the SEAL raid that killed bin Laden in Pakistan in 2011. "I think they're not good people".
Brennan does not face any formal charges of violating any regulations or laws. His criticisms provoked Trump to tweet this week, quoting a former Secret Service agent, calling Brennan a "stain" on our country.
Reactions from Republican lawmakers were mixed, with some critical of Trump while others blamed Brennan for acting inappropriately. U.S. Representative Joaquin Castro said Mueller should also investigate the issue now that Trump tied it to the Russian Federation probe. However, he said the move would be a "powerful piece of evidence" for prosecutors as part of a pattern to demonstrate an intent to use presidential power in connection with the investigation.
"It's an abuse of power because he's not doing it for a legitimate reason", Castro told CNN.