FBI chief James Comey felt 'obligation' to reveal new Clinton emails probe
FBI Director James Comey has said that it would have misled the American people if he had not revealed there was a new probe into Hillary Clinton's emails.
The timing of the announcement, so close to the November 8 presidential election, has led to criticism that he was trying to influence its outcome.
However, if he had waited until after Election Day, the career prosecutor who has served under both Republican and Democratic administrations would surely have faced criticism for sitting on major news until after the new president had been selected.
In an internal email to FBI employees, obtained by The Associated Press, Mr Comey wrote: "Of course, we don't ordinarily tell Congress about ongoing investigations, but here I feel an obligation to do so given that I testified repeatedly in recent months that our investigation was completed.
"I also think it would be misleading to the American people were we not to supplement the record."
The FBI is investigating whether there is classified information in new emails uncovered during the sexting investigation of disgraced former congressman Anthony Weiner, the estranged husband of one of Hillary Clinton's closest aides.
Mr Comey earlier told Congress in a letter the emails prompted investigators to look again at whether classified information had been mishandled, the focus of its recently closed, criminal probe into Mrs Clinton's use of a private email server.
He could not guarantee that the latest focus of the investigation would be finished before Election Day.
Mr Comey did not provide details about the emails, but a US official told The AP that the emails emerged through the FBI's separate sexting probe of Mr Weiner, who is separated from Clinton confidant Huma Abedin.
She served as deputy chief of staff at the State Department and is still a key player in Mrs Clinton's presidential campaign.
The two separated earlier this year after Mr Weiner was caught in 2011, 2013 and again in 2016 sending sexually explicit text messages and photographs of himself undressed to numerous women.
Authorities in New York and North Carolina are investigating online communications between Mr Weiner and a 15-year-old girl.
Mr Comey stressed in his letter that the FBI could not yet assess "whether or not this material may be significant," or how long it might take to run down the new investigative leads.
"In connection with an unrelated case, the FBI has learned of the existence of emails that appear to be pertinent to the investigation," he wrote.
"I agreed that the FBI should take appropriate investigative steps designed to allow investigators to review these emails to determine whether they contain classified information, as well as to assess their importance to our investigation."
It was unclear what the emails contained, who sent them, or what connection they might have to the year-long investigation the FBI closed in July without recommending criminal charges.
The FBI probe focused on whether Mrs Clinton sent or received classified information using a server in the basement of her New York home, which was not authorised to handle such messages.
Mr Comey said in July that his agents did not find evidence to support a criminal prosecution or direct evidence that Mrs Clinton's private server was hacked.