A 21-year-old US Air Force National Guard member has been arrested over the leak of US defence and intelligence documents.
Jack Teixeira is reported to be the leader of an online gaming chat group where the files were leaked.
The documents revealed sensitive intelligence about the war in Ukraine and other countries around the world.
Aerial footage showed officers making an arrest at Mr Teixeira's family home on Thursday.
The arrest happened in Dighton, a town of 8,000 people about an hour to the south of Boston.
Footage of the arrest shows a young man, believed to be Mr Teixeira, walking backward towards armed FBI officers with his hands raised before he is handcuffed and led to a car.
The New York Times used interviews and social media clues to identify Mr Teixeira - a member of the intelligence wing of the Massachusetts Air National Guard - before the confirmation of his arrest.
The FBI said in a statement the arrest happened "without incident" and that agents were continuing to investigate at the home.
What was in the leaks?
Starting several months ago, at least 50 but perhaps more than 100 classified documents were posted on Discord - a social media platform popular with gamers.
The documents - which BBC News is examining - contain a range of intelligence assessments about the war in Ukraine, but also sensitive intelligence about countries around the world, including US allies.
A Department of Defense spokesman has said the Pentagon is continuing to work to "understand the scope, scale and impact of these leaks".