BBC:-FBI director James Comey has told Congress the bureau is reopening its inquiry into Hillary Clinton’s emails.
Investigators have discovered new emails “in connection with an unrelated case… that appear to be pertinent to the investigation”, he said.
Mr Comey said investigators would determine whether the emails contain classified information.
The FBI has already found the Democratic candidate had classified information on a private email server.
Mr Comey had previously called Mrs Clinton’s handling of classified information during her time as secretary of state “extremely careless”, but cleared her of any criminal wrongdoing.
The FBI chief said in his letter to Congress he “cannot yet assess whether or not this material may be significant, and I cannot predict how long it will take us to complete this additional work”.