The Massachusetts Air National guard member who leaked troves of classified military documents and posted them online in a case considered one of the most serious US national security breaches in recent years agreed to accept a 16-year sentence on Monday.

Jack Teixeira, who was 21 at the time of his arrest in April 2023, was accused of abusing his security clearance and leaking top-secret Pentagon documents and sharing them on the social media and gaming app Discord.

The documents were then widely shared.

The highly classified documents he was accused of disclosing included detailed intelligence assessments of Russia’s invasion of Ukraine, including “how the equipment would be transferred, and how the equipment would be used upon receipt,” according to the indictment.

This is a developing story. Check back for updates.