Donald Trump's campaign manager has stated the FBI's decision to reopen the investigation into the use of Hillary Clinton's email server is "a great day" for the GOP nominee's campaign.

FBI director James Comey wrote to members of Congress on 28 October, explaining the FBI had learned of the existence of emails that appeared to be pertinent to the investigation into Clinton's use of a private email server, and would be reopening the probe.

The decision comes just 11 days before the US presidential election, and was described by Trump's campaign manager Kellyanne Conway as a positive for the GOP nominee.

She tweeted: "A great day in our campaign just got even better. FBI reviewing new emails in Clinton probe," linking to an article about the investigation being reopened.

Trump also responded with a statement about the investigation, following months of the GOP nominee suggesting the emails should have been investigated further, despite the FBI previously closing the investigation.

He said: "I need to open with a very critical breaking news announcement. The FBI has just sent a letter to Congress informing them that they have discovered new emails pertaining to former Secretary of State Hillary Clinton's investigation, and they are reopening the case into her criminal and illegal conduct that threatens the security of the United States of America.

"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.

"I have great respect for the fact that the FBI and the DOJ are now willing to have the courage to right the horrible mistake that they made. This was a grave miscarriage of justice that the American people fully understand. It is everybody's hope that it is about to be corrected."

Trump had suffered several of his own setbacks in recent weeks, including the release of footage of him making lewd comments about women, accusations he has avoided paying certain taxes for 18 years, and allegations of sexual assault from a number of women.

Clinton's campaign chairman John Podesta also issued a statement in response to Comey's letter, which has been shared on social media platforms.