The 21-year-old arrested in connection with the leaked documents probe has been charged with unauthorized retention and transmission of national defense information and willful retention of classified documents, which collectively carry a maximum of 15 years in prison.

Jack Teixeira, a member of the Massachusetts Air Force National Guard, made his initial appearance before a federal magistrate in Boston on Friday morning.

Teixeira walked into court in a beige smock and pants with a black T-shirt underneath. He entered in handcuffs, which were removed before he sat at the defense table with his attorney. Teixeira appeared to briefly scan the crowd while in his seat.

Three people sat on a bench in the front row reserved for relatives of the defendant.

As Teixeira was re-handcuffed and led from court, someone in the front row called out, "Love you, Jack." The 21-year-old responded, "Love you, too, dad."

Assistant U.S. Attorney Nadine Pellegrini sought pretrial detention, which was granted pending the outcome of a hearing on Wednesday.

Teixeira was taken into custody in Massachusetts on Thursday "in connection with an investigation into alleged unauthorized removal, retention and transmission of classified national defense information," Attorney General Merrick Garland announced.

Media reports have described the U.S. intelligence documents -- which seem to contain top-secret information about the Ukraine war and other parts of the world -- as being shared among a small group of users on Discord before getting wider notice.