The FBI has notified the US Congress it will investigate new emails found in the probe of Hillary Clinton's private server.
The FBI is investigating whether new emails that may contain classified information have emerged in its probe of Hillary Clinton's private server.
The FBI said in July its investigation was finished.
The disclosure to the US Congress raises the possibility of the FBI reopening the criminal investigation involving the Democratic presidential nominee just days before the election.
Mrs Clinton's campaign did not immediately respond.
In a letter sent on Friday to congressional leaders, FBI director James Comey said new emails have come to light recently that have prompted investigators to take another look at the sensitive government information that flowed through the private email server Mrs Clinton used while serving as secretary of state.
It was not clear from Mr Comey's letter where the new emails came from or who sent or received them.