The FBI has discovered new emails that “appear to be pertinent” to the investigation into Hillary Clinton’s use of a private email server while she was secretary of state, according to a letter FBI Director James Comey sent to the chairs of pertinent congressional and senate committees Friday.

House Oversight Committee chair Rep. Jason Chaffetz, R-Utah, announced the FBI’s discovery of the emails.

But CBS News’ Jeff Pegues reports that the FBI is not yet saying that it’s reopening the investigation. That will depend on the outcome of its assessment of “whether or not this material may be signficant.” The FBI’s investigative team briefed Comey Thursday on the new emails. The FBI director also warned the committee chairs, “I cannot predict how long it will take us to complete this additional work.” Pegues also reports that the emails in question are not from the WikiLeaks release of Clinton campaign chairman John Podesta’s personal emails. 

Comey’s letter to Congress informed lawmakers that he was supplementing his previous testimony on the matter of the investigation, which was completed in July. At the time, Comey recommended no charges against Hillary Clinton, a recommendation accepted by the Justice Department.

A Republican congressional Intelligence Committee aide told CBS News’ Nancy Cordes that no one knows what new material the FBI has and called it “beyond crazy.” 

Following the release of the FBI letter, House Speaker Paul Ryan reiterated his call for the Director of National Intelligence to stop giving classified briefings to Clinton, the Democratic presidential nominee. 

“This decision, long overdue, is the result of her reckless use of a private email server, and her refusal to be forthcoming with federal investigators,” Ryan said in a statement. “I renew my call for the Director of National Intelligence to suspend all classified briefings for Secretary Clinton until this matter is fully resolved.”

State Department spokesman Mark Toner said Friday that the Department is trying to figure out what these emails pertain to and whether they’re relevant to Clinton’s time as secretary of state. 

Toner said they can’t make any assumptions that they are, “but they may be.” 

If so, Toner said the State Department is ready to cooperate with the FBI, but as of Friday afternoon, the department had not been contacted by the agency.

Donald Trump weighed in on the news at a Friday rally in Manchester, New Hampshire, saying that “perhaps justice will be done” after the FBI takes further investigative steps on the emails. 

The audience roared, “Lock her up! Lock her up,” as Trump declared, “Hillary Clinton’s corruption is on a scale we have never seen before...We must not let her take her criminal scheme into the Oval Office.” 

Trump also commended the FBI for now being “willing to have the courage to right the horrible mistake that they made” in announcing its investigation was complete. 

“This was a grave miscarriage of justice that the American people fully understood and it is everybody’s hope that it is about to be corrected,” he said. 

Later, Trump said of the “system” he has claimed to be “rigged” for several weeks: “It might be not be as rigged as I thought. I think they’re going to right the ship, folks. I think they’re going to right this yet.”

John Podesta, Clinton’s campaign chair, called on Comey in a statement to “immediately provide the American public more information than is contained in the letter” sent to Senate and House committee chairmen.

“Director Comey’s letter refers to emails that have come to light in an unrelated case, but we have no idea what those emails are and the Director himself notes they may not even be significant,” Podesta wrote Friday afternoon. “The Director owes it to the American people to immediately provide the full details of what he is now examining. We are confident this will not produce any conclusions different from the one the FBI reached in July.”

He added that, in the months since the email investigation was completed, partisan efforts have continued to undermine the agency. 

“Donald Trump and his Republican allies have been baselessly second-guessing the FBI and, in both public and private, browbeating the career officials there to revisit their conclusion in a desperate attempt to harm Hillary Clinton’s presidential campaign,” Podesta said.

CBS News’ Jeff Pegues, Catherine Reynolds and Steven Portnoy contributed to this report

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