A group of 13 former senior intelligence officials who served under both Democratic and Republican presidents denounced current President Donald Trump's decision to revoke former CIA Director John Brennan's security clearance, which they say was an "attempt to stifle free speech." The former senior intelligence officials, which includes former CIA directors, former CIA deputy directors as well as a former director of national intelligence, released a statement Thursday in which they unequivocally condemned the president's decision saying, "we all agree that the president's action regarding John Brennan and the threats of similar action against other former officials has nothing to do with who should and should not hold security clearances — and everything to do with an attempt to stifle free speech." They went on to argue that "beyond that, this action is quite clearly a signal to other former and current officials," and that "we have never before seen the approval or removal of security clearances used as a political tool, as was done in this case." 50 CELEBRITIES WHO DIED IN 2018 – TRIBUTE SLIDESHOW Michael Hayden, a former director of the NSA and CIA as well as one of the signatory's told CNN on Friday that making the decision to sign the statement wasn't all that difficult. "Using the security clearance process to punish a political opponent was simply inappropriate even though we admit that the president has absolute authority in this area," Hayden said. "It's just a bad thing to do for the health of the American republic and the health of American debate. DONALD TRUMP'S 30 CRAZIEST TWEETS President Trump first announced the revocation of Brennan's security clearance on Wednesday where he connected the reasoning behind the move citing security risks. However, the president later, in an interview with the Wall Street Journal cited Brennan's involvement in the Russia investigation, which he referred to as a "witch hunt" that "these people led."