The Pentagon will change its security policies after a review into a big leak of classified files found officials struggled to keep up with the number of staff who had top secret access.
New measures include the appointment of officers to control the level of access to top secret data and installing systems to detect electronic devices.
It follows the unauthorised publication of dozens of classified files online.
Ex-airman Jack Teixeira, 21, is charged with leaking files, which he denies.
The results of a 45-day review of Pentagon policies and procedures, ordered by US Defence Secretary Lloyd Austin in the wake of the leak, suggested the need to increase oversight for those trusted with classified national security information.
A senior defence official suggested to reporters at a briefing that Pentagon security protocols had struggled to keep pace with the growth in the number of cleared personnel and the number of facilities where secret files are accessed.
While some existing policies will be reinforced, others will be updated and new rules developed to address existing gaps, the defence department said.
The review concluded there was no “single point of failure” in the military’s procedures, and said the overwhelming majority of staff with access comply with security policies and procedures.
But it recommended the defence department increase its spending on security measures, create a new office for insider threats, and increase the number of staff overseeing the handling of classified documents.
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Watch: How damaging were Jack Teixeira’s alleged leaks?
The review suggested tightening security measures to prevent the use of electronic devices inside rooms where classified data is held and where confidential information or images could be photographed or recorded.
Mr Teixeira, who is in prison awaiting trial after being arrested in April, allegedly leaked files on the online chatroom platform Discord, a popular hangout for gamers.
According to prosecutors, Mr Teixeira wrote versions of sensitive information and posted it to the chatroom. Later, he is said to have shared photos of US intelligence material after he grew frustrated with a lack of response from the group’s users.
Mr Teixeira, a former member of the Air National Guard 102nd Intelligence Wing based in Massachusetts, faces up to 15 years in prison over charges of unauthorised transmission of defence information.
He pleaded not guilty to six federal counts of wilful retention and transmission of national defence information in June.
