Hillary Clinton urged FBI Director James Comey to release more details about the nature of the investigation as soon as possible, amid the revelation Friday that the FBI was reopening its probe into her use of a private email account.

"The American people deserve to get the full and complete facts. The director himself has said that he doesn't know whether the emails… are significant or not," Clinton said, in an impromptu Friday evening press conference. "It's imperative that the Bureau explains this issue in question, whatever it is, without delay."

Earlier in the day Comey notified members of Congress that the bureau had recovered emails in "connection with an unrelated case...that appear to be pertinent to the investigation," and was resuming its investigation into whether Clinton violated any laws by using a private email server for official business.

"Right now, your guess is as good as mine. And I don't think that's good enough," Clinton said. "If they're going to be sending this kind of letter… then they need to share whatever facts they claim to have with the American people."

Clinton also tried to downplay the significance of the latest development in her email scandal, occurring just 11 days before most Americans go to the polls.

"People, a long time ago, made up their minds about the emails. I think that's factored in… and now they're choosing a president," Clinton said.

—Tim Mak