FBI Director James Comey said on Wednesday it made him feel "mildly nauseous" to think he had an impact on the 2016 US presidential election, but that he had no choice but to announce just days before the vote that the agency had reopened a probe into Democratic candidate Hillary Clinton's emails.
Comey told the Senate Judiciary Committee that one reason for the FBI's renewed interest in Clinton's emails ahead of the Nov. 8 election was that investigators had found emails, some of which were classified, forwarded by Clinton's assistant Huma Abedin to her husband who was not authorised to see such information.
TRT World's Kate Fisher brings more from Washington DC
Clinton said on Tuesday that her election bid was derailed in part by Comey's announcement about the renewed probe of her use of a private email server while she was secretary of state. She also said her bid to defeat Republican Donald Trump was damaged by the WikiLeaks release of her campaign chairman John Podesta's emails, allegedly stolen by Russian hackers.
Comey told the Senate panel he felt he had to speak out last year about the email probe because he had repeatedly told Congress the investigation was over.
"To not speak about it would require an act of concealment in my view,” Comey said. "Concealing, in my view, would be catastrophic."
The FBI, which is supposed to remain politically neutral, said a few days later that the new emails did not change an earlier decision not to recommend criminal charges against Clinton, but many Democrats believe the political damage was done.
US intelligence agencies in December accused Russia of hacking of Democratic emails in an effort to tilt the election to Trump. Comey confirmed in March the FBI was investigating possible collusion between Trump surrogates and Russia.
Comey said on Wednesday the probe into whether Russian hacking activities and American citizens was a classified investigation in its early stages, far different from the almost completed email probe.
Comey declined to comment on whether Trump, or anyone else, had been ruled out as a possible subject. Moscow has denied the hacking allegations.
The FBI director acknowledged recent months have been difficult.
"But I think I've done the right thing at each turn. I'm not on anybody's side. It's so hard for people to see that," Comey said, adding later, "I don't have any regrets."