Comey's comments in an ABC News interview that aired Sunday were nearly certain to escalate his war of words with the president and further erode a relationship marked by open hostility and name-calling.
Trump and his aides have countered Comey's media blitz by attacking his handling of the probe into Clinton's emails.
Russian Federation has denied interfering in the election and Trump has denied any collusion or improper activity. Trump has called the special counsel probe a "witch hunt" and repeatedly insisted there was no collusion between his campaign and Russian Federation.
The FBI director, who until his firing last May led an investigation into possible ties between Russian Federation and the Trump campaign, acknowledged that it was "stunning" to think Russian Federation could have damaging information on an American president.
"He has no credibility and President Trump was right to follow through on the bipartisan calls for him to be fired", McDaniel said in a statement.
'I did not go into the business about- people peeing on each other, I just thought it was a weird enough experience for me to be talking to the incoming president of the United States about prostitutes in a hotel in Moscow.
'You can't say for certain that the president of the United States is not compromised by the Russians?' pressed Stephanopoulos.
Comey said he doesn't "buy" into speculation that Trump is "medically unfit" to be president, but rather condemned the president's ethics largely due to his handling of Charlottesville and, as Comey put it, his treatment of women "like they're pieces of meat". And it's illustration of our polarization here that you've got the Trump camp, which I guess thinks I was trying to save Hillary Clinton. "Just another of his many lies", Trump said on Twitter. Comey adds, "It was all, 'What can we say about what they did and how it affects the election that we just had?'"
In attempt to blunt the impact of the new book, the Republican National Committee is waging a widespread campaign to undercut Comey's credibility, including a new website that dubs the former Federal Bureau of Investigation chief as "Lyin' Comey".
Many Democrats blamed Comey for Clinton's defeat, as his revelation shifted momentum to Trump in the final news cycles of the campaigns.
A big topic of discussion in Comey's interview was his effect on the 2016 presidential campaign.
In a pair of tweets, Trump accused Comey of leaking classified information and lying to Congress under oath. But Comey couldn't possibly have tipped the election to such a man because his actions possibly made no difference. The polls swung considerably against Hillary Clinton after Comey's October 28 announcement, and didn't recover when he declared two days before the election that the investigation hadn't actually turned up anything incriminating about her. No, in fact, as I said, the information that triggered it was the Papadopoulos information that came in late July.
"I think it's possible", Comey replied.
At one point in the interview, Stephanopoulos asks Comey how odd it must feel to make that comparison.
Two Republican and two Democratic senators introduced a bill to make it more hard and time-consuming for Trump to fire Mueller, titled the "Special Counsel Independence and Integrity Act", last week. He asked, "Why can't we all find out what happened on the tarmac in the back of the plane", in the June 2016 meeting between Bill Clinton and then-Attorney General Loretta Lynch, one month before the Justice Department cleared Hillary Clinton of criminal charges in the investigation into her use of a private email server while secretary of state.