Washington, Oct 31 (IANS): The US State Department has released 7,000 more pages of Democratic presidential hopeful Hillary Clinton's e-mails, the largest batch to date from a private server she used for official business during her 2009-2013 tenure as secretary of state.

The e-mails were released on Friday by order of federal Judge Rudolph Contreras, who instructed the State Department to disclose them on a monthly basis through January 2016, EFE news reported.

A total of 30,000 e-mails are to be released; around half have been released so far.

Clinton acknowledged having used the personal server to conduct government business, an unconventional arrangement that became public in March.

This latest batch is the first to be released since Clinton testified last week before Congress about the use of the private server and the 2012 attack on the US diplomatic compound in Benghazi, Libya.

The most recently released e-mails mostly date back to 2011 and 2012, although some were sent in 2009 and 2010, State Department spokesman John Kirby said.

Between 200 and 300 of the e-mails have been elevated to the category of "confidential" because they were found to contain confidential information after being reviewed by the State Department, the spokesman said.

The information in the e-mails was not classified at the time the e-mails were sent, he noted.

Clinton has said she used the server as "a matter of convenience".

"I thought it would be easier to carry just one device," she said, adding that "looking back it would have been better if I had simply used a second e-mail account and carried a second phone."