An international manhunt is now on for the perpetrator of what is believed to be the most serious US military intelligence leak since the stash of sensitive material released by Edward Snowden a decade ago.

Little is known about the identity of the leaker but he is thought to be a gun enthusiast in his 20s who obtained classified documents while working on a US military base, before posting them on a group chat section of Discord, an encrypted instant messaging platform used by gamers.