John Brennan
John BrennanReuters

Former CIA chief John Brennan doubled down Sunday on his charge that President Donald Trump has engaged in "treasonous" behavior, calling on Congress to block his attempts to strip other intelligence officials of their security clearances, AFP reported.

Last week, Trump revoked Brennan’s security clearance and later said the move was directly tied to the investigation into Russia’s interference in the 2016 presidential election.

In July it was reported that Trump was considering pulling the national security clearances of top-level former intelligence officials for making what the White House described as "baseless accusations" against him.

In addition to Brennan, those former officials reportedly included former FBI Director James Comey, former NSA Director Michael Hayden, former U.S. national security advisor Susan Rice and former FBI Deputy Director Andrew McCabe.

All of those federal officials served during the Obama administration, and all have been vocally critical of Trump since leaving their posts in government.

In an interview on Sunday with NBC's "Meet the Press," Brennan reaffirmed his accusation against the president.

"I called his behavior treasonous. I stand very much by that claim," he stressed. "These are abnormal times ... I have seen the signs blinking red on what Mr. Trump has done and is doing."

Brennan made the charge after Trump met with Russian President Vladimir Putin in Helsinki last month and cast doubt on the U.S. intelligence conclusion that Moscow meddled in the 2016 election.

Earlier this week, Brennan denounced as "hogwash" Trump's repeated claim there was "no collusion" with Russia.

"This is the time for members of Congress to step up," he said on NBC on Sunday, referring to a move by Democrats in the Senate to constrain the president's ability to revoke clearances without following the normal process.

Last Wednesday, hours after Trump’s announcement, Brennan fired back and wrote on Twitter, “This action is part of a broader effort by Mr. Trump to suppress freedom of speech and punish critics. It should gravely worry all Americans, including intelligence professionals, about the cost of speaking out. My principles are worth far more than clearances. I will not relent.”