Washington (CNN) President Donald Trump slammed James Comey on Friday as a "weak and untruthful slime ball" and a "proven LEAKER & LIAR," the day after explosive excerpts from the former FBI director's tell-all book surfaced in media reports.

"James Comey is a proven LEAKER & LIAR. Virtually everyone in Washington thought he should be fired for the terrible job he did-until he was, in fact, fired. He leaked CLASSIFIED information, for which he should be prosecuted. He lied to Congress under OATH," Trump tweeted. "He is a weak and untruthful slime ball who was, as time has proven, a terrible Director of the FBI. His handling of the Crooked Hillary Clinton case, and the events surrounding it, will go down as one of the worst "botch jobs" of history. It was my great honor to fire James Comey!"

James Comey is a proven LEAKER & LIAR. Virtually everyone in Washington thought he should be fired for the terrible job he did-until he was, in fact, fired. He leaked CLASSIFIED information, for which he should be prosecuted. He lied to Congress under OATH. He is a weak and..... — Donald J. Trump (@realDonaldTrump) April 13, 2018

....untruthful slime ball who was, as time has proven, a terrible Director of the FBI. His handling of the Crooked Hillary Clinton case, and the events surrounding it, will go down as one of the worst "botch jobs" of history. It was my great honor to fire James Comey! — Donald J. Trump (@realDonaldTrump) April 13, 2018

Comey's book "A Higher Loyalty," of copy of which CNN obtained, details his conversations with the President, compares Trump to a mob boss, and slams the "forest fire that is the Trump presidency."

Comey testified in June that he gave some of his memos of conversations he had with Trump to a Columbia University professor and that he had written the memos specifically to avoid including classified information.

White House press secretary Sarah Sanders also attacked Comey's credibility Friday.

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