The US claims Russia or pro-Russian elements are likely behind the leak of classified military documents on social media.
The secret Pentagon documents that were discovered on 4chan, Twitter, Telegram and other websites were related to Ukraine, the Middle East and China. They also appeared to detail US and NATO aid to Ukraine, but may have been altered or used as part of a misinformation campaign.
Three US officials told Reuters that they believed Russia was behind the leak.
The Justice Department said it was investigating the leak that was first reported by the New York Times on Friday.
The NYT report had come after the Pentagon said it was reviewing how the handful of documents were released on several social media sites.
The files included secret briefing slides on China, the Indo-Pacific military theatre and details about the Middle East and terrorism among other things.
One of the leaked documents consisted of a map that purported to show the status of fighting currently underway in the eastern Ukrainian city of Bakhmut.
Other documents include Ukrainian air defense positions, combat equipment numbers and maps of the combat situations in Kharkiv and southern Ukraine, according to the New York Post.
A senior intelligence official told NYT that the leak is “a nightmare for the Five Eyes” intelligence grouping which consists of the US, Britain, Australia, New Zealand and Canada.
“We are aware of the reports of social media posts, and the Department is reviewing the matter,” Pentagon deputy press secretary Sabrina Singh said on Friday, right before the new documents surfaced.
After the documents were leaked, Ms Singh said in a statement: “The Department of Defense is actively reviewing the matter, and has made a formal referral to the Department of Justice for investigation.”
At least five photos of slides and maps were also posted, with three of the photos labeled “Secret” and one labeled “Top Secret,” according to the New York Post.
