James Comey
James ComeyReuters

FBI Director James Comey was driven in part by a fear of leaks from within his agency when he decided to tell Congress the agency was investigating newly discovered emails related to Hillary Clinton, law enforcement sources told Reuters on Thursday.

The examination of the email traffic is now being carried out under the tightest secrecy by a team at FBI headquarters in Washington, the sources told the news agency, speaking on condition of anonymity.

Several sources indicated it was unclear whether the FBI would make any further public disclosures about its latest review before Tuesday's presidential and congressional elections. Two sources said such disclosures were unlikely.

Another source, recently in contact with top investigators, told Reuters,"It depends on how it goes and what they find." The source said that, as of Thursday, "nobody really knows" whether the FBI will have anything further to say before the election.

Comey dropped a bombshell last Friday when he announced his office was pursuing potential new evidence related to Clinton’s use of a private email server as Secretary of State.

The latest emails under investigation are related to a separate probe of former congressman Anthony Weiner, who is alleged to have exchanged explicit sexual messages with a 15-year-old girl and who is the estranged husband of close Clinton associated Huma Abedin.

Comey's disclosure in a letter to senior lawmakers just days before the elections raised questions about his motives and drew criticism from some – mostly Clinton supporters – over his timing.

Comey disclosed that the FBI was looking at emails as part of a probe into Clinton's use of a private email system while Secretary of State, without describing the emails' content or how long the inquiry might take. The FBI normally does not comment on ongoing inquiries.

The latest emails examination was moving forward "expeditiously," one source close to the review told Reuters.

The Justice Department informed lawmakers earlier this week that it would work closely with the FBI in order to speed up the investigation.

The FBI has made preliminary inquiries into Clinton Foundation activities and alleged contacts between Trump and associates with parties in Russia, according to law enforcement sources who spoke to Reuters. However, these inquiries were shifted into low gear weeks ago because the FBI wanted to avoid any impact on the election.

The FBI previously had spent about a year investigating Clinton's use of the unauthorized server at her home in Chappaqua, New York, instead of the State Department system after classified government secrets were found in some of her emails.

Comey had said in July that while there was "evidence of potential violations of the statutes regarding the handling of classified information, our judgment is that no reasonable prosecutor would bring such a case."