Defense Secretary Lloyd Austin on Thursday ordered a review of US “intelligence access, accountability and control procedures” in the wake of the biggest national security breach in 10 years.

Austin announced the review in a statement where he also commended the Justice Department and FBI for their work apprehending Jack Teixeira, the 21-year-old Massachusetts Air National Guardsman implicated in the leak of dozens of highly sensitive Ukraine war documents. 

“The Department of Defense, in close partnership with the Intelligence Community and our interagency partners, will continue to review the national security implications of this unauthorized disclosure,” Austin said of the leaks.  

“As Secretary of Defense, I will also not hesitate to take any additional measures necessary to safeguard our nation’s secrets. Accordingly, I am directing the Under Secretary of Defense for Intelligence and Security to conduct a review of our intelligence access, accountability and control procedures within the Department to inform our efforts to prevent this kind of incident from happening again,” he added. 

Teixeira, a junior airman with the Air National Guard’s 102nd Intelligence Wing, worked as a cyber transport systems journeyman. 

US officials have not said whether he had a security clearance that would allow him to access the information that made its way onto the internet. 

Teixeira reportedly uploaded troves of secret and top secret documents to a private Discord server from which they were spread across several websites.

Pentagon spokesman Brig. Gen. Patrick Ryder on Thursday called the leak a “deliberate criminal act.” 

In his statement, Austin reminded service members and others with access to state secrets that they have a “solemn legal and moral obligation” to protect the sensitive information that is shared with them.

“Finally, I want to underscore that every U.S. service member, DoD civilian and contractor with access to classified information has a solemn legal and moral obligation to safeguard it and to report any suspicious activity or behavior,” Austin said.