President Trump blasted “slippery” James Comey as “the worst FBI Director in history” early Wednesday, claiming he was not fired over the “phony” Russia investigation and again insisting there was “NO COLLUSION” between his campaign and the Kremlin during the 2016 race.

Trump launched yet another full-throttled Twitter attack against the former FBI chief a day after his memoir “A Higher Loyalty” hit stores nationwide. Comey is ramping up TV appearances in promotion of the book, armed with tough criticism of his former boss, Trump.

“Slippery James Comey, the worst FBI Director in history, was not fired because of the phony Russia investigation where, by the way, there was NO COLLUSION (except by the Dems)!” Trump tweeted Wednesday.

COMEY ADMITS DRAFTING CLINTON EXONERATION BEFORE INTERVIEW, DEFENDS MOVE AS ROUTINE

Trump and his team have given varying explanations for why Comey was fired nearly a year ago. Days after accepting Deputy Attorney General Rod Rosenstein’s recommendation to terminate the FBI chief last May (based in part on how he handled the Clinton email probe), Trump told NBC News’ Lester Holt that he fired Comey because he was a “showboat” and “was not doing a good job.”

“Regardless of recommendation, I was going to fire Comey,” Trump told NBC News last May. “And, in fact, when I decided to just do it, I said to myself, ‘You know, this Russia thing with Trump and Russia is a made up story.’ It’s an excuse by the Democrats for having lost an election that they should have won.”

Democrats have long claimed he removed Comey over his handling of the Russia investigation. They also cite a meeting in the Oval Office where, Comey claims, Trump asked him to go easy on his former National Security Adviser Michael Flynn.

COMEY CALLS TRUMP 'MORALLY UNFIT TO BE PRESIDENT', SAYS HE WOULDN'T HAVE CHANGED HANDLING OF CLINTON PROBE

This week, Comey has done multiple high-profile interviews to promote his new book – the first, airing in a Sunday night special on ABC News with George Stephanopoulos.

Tuesday night, Comey appeared on Stephen Colbert’s late night show, saying his termination came as a surprise.

“I thought, I’m leading the Russia investigation. Even though our relationship was becoming strained, there’s no way I’m going to get fired,” Comey told Colbert.

Comey, who, for decades, has been a registered Republican, said this week that he no longer considers himself a Republican.

“The Republican Party has left me and many others,” Comey said in ABC News podcast “Start Here” this week. “I just think they’ve lost their way and I can’t be associated with it.”

Comey also said this week that Trump was “morally unfit to be president,” but did not suggest impeachment as a remedy.

“I think impeaching and removing Donald Trump from office would let the American people off the hook and have something happen indirectly that I believe they’re duty bound to do directly,” Comey said during his interview with Stephanopoulos, adding that people “need to stand up” and “go to the voting booth and vote their values.”

Trump has ramped up attacks on Comey in the last week, calling him an “untruthful slime ball,” a “liar” and a “leaker.”

And Comey has compared Trump to a "mob boss" and an "obsessive ex-boyfriend."