The FBI has shared secret documents from its investigation of Democratic presidential candidate Hillary Clinton with members of Congress, fulfilling at least in part a promise the bureau's director made last month.
A spokeswoman for the House Oversight and Government Reform Committee confirmed the panel had received "a number of documents" from federal investigators Tuesday afternoon.
"Committee staff is currently reviewing the information that is classified SECRET," the spokeswoman said. "There are no further details at this time."
Another source familiar with the release described the materials as interview notes of Clinton and others and emails connected to the personal server Clinton used during her tenure as secretary of state to conduct government business.
Last month, FBI Director James Comey concluded Clinton had been "extremely careless" but said "no reasonable prosecutor" would have pursued a criminal case against Clinton or her close aides. Comey testified before the House Oversight panel July 7, when he told lawmakers Clinton had been truthful with the bureau during a 3 1/2 hour interrogation at FBI headquarters.
In a statement, the FBI said it was providing additional materials to lawmakers "consistent with our commitment to transparency" with congressional overseers about the Clinton investigation. A bureau spokeswoman took care to note the documents were not for public consumption.
"The material contains classified and other sensitive information and is being provided with the expectation it will not be disseminated or disclosed without FBI concurrence," she added.
The release of fresh information on the criminal investigation remains controversial with many Democrats and Justice Department veterans. Within the Obama administration, lawyers debated whether giving Congress access to materials on a closed case might set a risky precedent.
Rep. Adam Schiff, a Democrat from California who once served as a federal prosecutor, said the House Intelligence Committee had also received "witness interview reports" on the Clinton email probe.
"This will neither serve the interests of justice nor aid Congress in its responsibilities and will merely set a precedent for the FBI to turn over closed case files whenever one party in Congress does not like a prosecutorial decision," Schiff said. "This has been done in the name of transparency, but as this precedent chills the cooperation of other witnesses in the future, I suspect the Department of Justice will later come to refer to it by a different name – mistake."
At the State Department Tuesday, spokesman Mark Toner said the department had not yet reached an agreement with the FBI about whether "witness interview summaries" should be shared widely. Toner said authorities at State respect "the FBI's desire to accommodate the requests of its committees of oversight in Congress... and we are going to continue to cooperate just as we have with the FBI in every step of the process."
On the campaign trail, the issue of Clinton's private server is unlikely to fade anytime soon. The FBI recovered tens of thousands of emails in the course of its investigation, which it has handed over to State for release to the conservative nonprofit Judicial Watch.
Judicial Watch has been scouring the material for connections between Clinton's State Department and donors to the Clinton Foundation.
"The American people will now see more of the emails Hillary Clinton tried to hide from them," the group's president, Tom Fitton, said in a written statement.
State Department Correspondent Michele Kelemen contributed to this report.