They said it "has nothing to do with who should and should not hold security clearances - and everything to do with an attempt to stifle free speech".
In an opinion piece in The New York Times, former CIA Director John Brennan said Trump's decision, announced Wednesday, to deny him access to classified information was a desperate attempt to end Mueller's investigation.
Mr Ohr has come under Republican scrutiny for his contacts to Glenn Simpson, co-founder of Fusion GPS. The opposition research firm hired former British spy Christopher Steele during the 2016 USA presidential campaign to compile the dossier on Trump and his Russian Federation ties.
Amid mounting criticism after he revoked the former Central Intelligence Agency director John Brennan's security clearance, Donald Trump threatened to similarly punish a current official and is reportedly preparing to do the same to others who have criticized him.
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The statement also claimed that Brennan had been "leveraging" his clearance to make "wild outbursts" and claims against the Trump administration in the media.
The White House said it was studying a list of other individuals for security clearance review, and Trump suggested Ohr was at the top of that list. In an interview with The Wall Street Journal, Trump again called the probe a "rigged witch hunt" and said "these people led it!"
A series of stories surrounding President Trump and the White House filled the news this week, and political cartoonists were quick to put their spin on things.
All materials, including briefing reports and memos, audio/video presentations, PowerPoint presentations and any other records, used by CIA Director Brennan and/or other CIA officials to brief Senator Reid and/or members of his staff on alleged "collusion" between the Trump presidential campaign and Russian Federation.
Besides Gates, those signing the letter included former CIA directors William H. Webster, George J. Tenet, Porter Goss, Michael V. Hayden, Leon E. Panetta and David H. Petraeus; former director of national intelligence James R. Clapper Jr.; and former deputy CIA directors John McLaughlin, Stephen Kappes, Avril Haines, David Cohen and Michael Morell. The case, which has been winding its way through the federal court in Washington, D.C., was brought against the Taliban, the Islamic Republic of Iran, Afghanistan, its former President Hamid Karzai and other terrorist defendants. Brennan described Trump's actions at a summit with Russian President Vladimir Putin in Helsinki last month as treasonous.
"Beyond that, this action is quite clearly a signal to other former and current officials", the former officials said, adding that the signal "is inappropriate and deeply regrettable".
Former officials often retain security clearance after leaving office to allow their successors to consult them on issues of the day.