PRESIDENT Donald Trump has once again called James Comey a “slimeball” ahead of the publication of the former FBI director’s book.

Trump’s morning tweet came before Comey’s prime-time interview on US television.

In an excerpt shown on Saturday, Comey explains that his belief that Hillary Clinton would win the 2016 presidential election was a motivating factor in his decision to disclose the FBI investigation into her emails.

In his tweet, Trump said: “Unbelievably, James Comey states that Polls, where Crooked Hillary was leading, were a factor in the handling (stupidly) of the Clinton Email probe. In other words, he was making decisions based on the fact that he thought she was going to win, and he wanted a job. Slimeball!”

The president had initially called Comey an “untruthful slimeball” on Friday, after details of his memoir first emerged.

Clinton has previously said that she believes questionable FBI decision-making –alongside misogyny and Russian interference – may have contributed to her 2016 election defeat.