FBI director James Comey said Sunday the agency is not recommending charges against Democratic presidential nominee Hillary Clinton after reviewing newly discovered emails, a report said.

Comey said the FBI is standing by its original findings, made in July, that Clinton should not be prosecuted for her handling of classified information over email as secretary of State, the USA Today report said.

"The FBI investigative team has been working around the clock to process and review a large volume of emails from a device obtained in connection with an unrelated criminal investigation," Comey said in the letter.

"During that process we reviewed all of the communications that were to or from Hillary Clinton while she was secretary of State. Based on our review, we have not changed our conclusions that we expressed in July with respect to Secretary Clinton."

Comey had rocked the presidential race with his announcement October 28 that the FBI had uncovered a new trove of emails that might be relevant to the investigation of Clinton's use of a private email server. The emails were discovered on the computer of Anthony Weiner, the estranged husband of Clinton aide Huma Abedin.