Hillary Clinton
Hillary ClintonReuters

A judge on Monday ordered the State Department to review and determine the potential release of 14,900 documents, most of which are believed to be emails to or from Hillary Clinton, that turned up in an FBI investigation of her use of a private email server as Secretary of State, Reuters reported.

The documents are part of a cache that the FBI turned over to the State Department at the end of its probe into Clinton's use of the server.

The FBI found Clinton was "extremely careless" with sensitive information by using the private server but recommended against bringing charges against Clinton. Nevertheless, she has been dogged by questions about the issue throughout her campaign for the White House.

Clinton has said she used private emails out of "convenience", though she has also admitted it "would have been better" to have two accounts to separate work and personal emails.

The State Department could make public the first batch of emails in October, weeks before the Democratic nominee faces Republican rival Donald Trump in the November 8 election. State Department employees are due to craft a timeline for the release at a meeting on September 23, according to Reuters.

Monday’s announcement by U.S. District Court Judge James Boasberg, who is overseeing a group of lawsuits seeking to make Clinton's emails public, came the same day a conservative watchdog group, Judicial Watch, made public a batch of Clinton's emails obtained through a lawsuit.

Judicial Watch says that the emails show donors to the Clinton family's charitable foundation seeking the access to her during the period she was secretary of state from 2009-2013.

The 14,900 documents referred to by Boasberg are believed to include emails that were not included among the 55,000 pages of emails that Clinton previously turned over to the State Department after her use of a private email server and private email account became public last year.

The new documents are believed to consist chiefly of emails to or from Clinton, said a U.S. official who spoke to Reuters on condition of anonymity, and may include a mix of personal and work emails.

Some of the emails were found on the servers of people she or her staff were communicating with, according to the news agency.

The FBI last week turned over a number of documents to the U.S. Congress related to its probe into the emails, but this has riled both Democrats and Republicans.

Democrats have expressed concern over the potential for politically motivated leaks by Republicans to target Clinton less than three months before the election.

The FBI has made clear to Congress it would expect it to obtain approval before releasing any of the documents that were turned over last week.