Washington (CNN) Former CIA director John Brennan is comparing President Donald Trump to foreign strongmen and vows to speak out until "integrity" is restored at the White House.

"For more than three decades, I observed and analyzed the traits and tactics of corrupt, incompetent and narcissistic foreign officials who did whatever they thought was necessary to retain power ... It never dawned on me that we could face such a development in the United States," the former intelligence official wrote in a blistering op-ed published Friday in The Washington Post.

Brennan, who oversaw the agency from 2013 to 2017, said that such authoritarian rulers work to discredit the media, interfere in the independence of the judiciary, and rely on "lies, deceit and suppression of political opposition to cast themselves as populist heroes and to mask self-serving priorities."

Brennan accused Trump of "lying routinely to the American people without compunction, intentionally fueling divisions in our country and actively working to degrade the imperfect but critical institutions that serve us."

The former CIA chief lamented that "the esteem with which I held the presidency was dealt a serious blow when Donald Trump took office."

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