Former CIA communications director Bill Harlow on Monday warned that President Trump Donald John TrumpSteele Dossier sub-source was subject of FBI counterintelligence probe Pelosi slams Trump executive order on pre-existing conditions: It 'isn't worth the paper it's signed on' Trump 'no longer angry' at Romney because of Supreme Court stance MORE could be setting a precedent for future administrations by taking away security clearances.

The comments come amid the fallout over the president's revocation of former CIA Director John Brennan John Owen BrennanJournalism or partisanship? The media's mistakes of 2016 continue in 2020 Comey on Clinton tweet: 'I regret only being involved in the 2016 election' Ex-CIA Director Brennan questioned for 8 hours in Durham review of Russia probe MORE's security clearance.

Harlow said “rules ought to be followed” and clearances should not be removed on a “whim.”

"If this administration takes away the clearances of people for speaking, the next administration could do the same," Harlow told Hill.TV's Krystal Ball and Buck Sexton on "Rising."

"There are rules and regulations on how you can take away people's clearances if they do something inappropriate. Those rules ought to be followed not just on [a] political whim," he continued.

Harlow is one of the dozens of former officials from the U.S. intelligence community who signed a letter condemning Trump for revoking Brennan's security clearance last week.

The White House accused Brennan of using his status as a former government official to make “unfounded and outrageous” charges about the administration.

Trump is also reviewing access to classified information for several former intelligence officials who have publicly criticized him or have come under attack from the White House.

The former officials include former FBI Director James Comey James Brien ComeySteele Dossier sub-source was subject of FBI counterintelligence probe Judge will not dismiss McCabe's case against DOJ Democrats fear Russia interference could spoil bid to retake Senate MORE, former national security adviser Susan Rice and former FBI Deputy Director Andrew McCabe.

Brennan said on Sunday that he would be willing to go to court to prevent the president from taking away additional security clearances.

"I’m going to do whatever I can personally to try to prevent these abuses in the future and if it means going to court, I will do that," Brennan said on NBC's "Meet the Press."

— Julia Manchester