Newly released documents show Defense Secretary Ash Carter used his personal email account for government business for nearly a year, until December 2015, when news reports revealed the practice.

The Pentagon late Friday released 1,336 pages of the emails in response to Freedom of Information Act requests by The Associated Press and other news organizations.

Pentagon press secretary Peter Cook says in a statement to the AP that the release shows that none of the emails contained classified information. Cook says all of Carter's work-related emails are preserved within the federal records system.

On Dec. 18, one day after the first news stories appeared, Carter sent an email on his personal account stating the he would no longer use personal email for the remainder of his tenure as defense secretary.