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.
The New York Times reports that many of the emails were heavily redacted, including one that says "for official use only," a designation normally reserved for "sensitive government information that is not classified."
Since 2012, the Defense Department has prohibited its employees from using personal email accounts for official work. Carter took the post of defense secretary in February 2015, a month before reports revealed former Secretary of State Hillary Clinton used a personal email account to conduct official business.
On Dec. 18, one day after the Times broke the story, 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.
At the time, Carter said the "mistake" was entirely his and that someone in his postion "should have known better."