US President Donald Trump has revoked the security clearance of former CIA Director John Brennan, accusing him of using his access to classified information to "sow division and chaos" about the Trump administration.
President Trump announced the decision in a statement read by White House press secretary Sarah Sanders at her daily news briefing.
Mr Trump said he was also reviewing the security clearances of several other former ranking government officials, all of whom have criticised Mr Trump, including former national intelligence director James Clapper, former FBI Director James Comey, former Obama national security adviser Susan Rice, former National Security Agency director Michael Hayden and former deputy Attorney General Sally Yates, among others.
John Brennan, who was director of the CIA under President Barack Obama, has been a sharp critic of Mr Trump, frequently appearing on cable television news shows to attack his foreign policy positions.
Mr Trump's statement said Mr Brennan had engaged in "increasingly frenzied commentary" and abused his access to classified information by using it to "sow division and chaos".
"At this point in my administration, any benefits that senior officials might glean from consultations with Mr Brennan are now outweighed by the risks posed by his erratic conduct and behaviour ... That conduct and behaviour has tested and far exceeded the limits of any professional courtesy that has been due to him," Mr Trump said.
Mr Brennan said the US president's decision to revoke his security clearance was part of an effort to silence critics.
"This action is part of a broader effort by Mr Trump to suppress freedom of speech and punish critics," he said on twitter.
"It should gravely worry all Americans, including intelligence professionals, about the cost of speaking out."
This action is part of a broader effort by Mr. Trump to suppress freedom of speech & 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. https://t.co/TNzOxhP9ux— John O. Brennan (@JohnBrennan) August 15, 2018
In an interview on MSNBC, Mr Brennan said Mr Trump's action was politically motivated.
The move against Mr Brennan came a day after the former CIA director denounced Donald Trump in a tweet for his criticism of Omarosa Manigault Newman, the former White House aide who wrote a book critical of the president.
"It's astounding how often you fail to live up to minimum standards of decency, civility, and probity. Seems like you will never understand what it means to be president, nor what it takes to be a good, decent, and honest person. So disheartening, so dangerous for our Nation," Mr Brennan wrote.
Following the president's summit last month with Russian leader Vladimir Putin, Mr Brennan described President Trump's behaviour as "nothing short of treasonous".