Alleged classified documents leaker Jack Teixeira pleads not guilty

Jack Teixeira, the Massachusetts Air National Guard member accused of leaking classified documents online, pleaded not guilty Wednesday to six counts of willful retention and transmission of national defense information.

The 21-year-old Massachusetts native was indicted by a grand jury earlier this month.

NOTE: The video in the media player is from a previous report.

Teixeira's family said in a statement Wednesday, "We remain as committed as ever and our entire family continues to share complete and unwavering support of Jack."

"Jack will now have his day in court. And as we move through this process, we are hopeful that Jack will be getting the fair and just treatment he deserves," the family said. "We realize there is a long road ahead, and we ask for your continued respect for our privacy during this difficult ordeal."

Teixeira is accused of abusing his security clearance and posting classified documents on social media sites, according to the Department of Justice. Teixeira allegedly revealed the kinds of military equipment the United States was prepared to give to Ukraine, "how the equipment would be transferred, and how the equipment would be used upon receipt," according to the indictment.

Teixeira has been in custody since his April arrest. Magistrate Judge David Hennessy on Wednesday denied a defense request to revisit pretrial detention.

Teixeira enlisted in the Air National Guard in 2019, according to his service record, and had top secret security clearance since 2021, according to the Department of Justice.

He allegedly began posting classified documents online in January 2022, according to the Justice Department.

Teixeira's next court date is set for Aug. 9 via telephone.

He could face 10 years in prison for each charge if convicted.

ABC News' Chris Donato contributed to this report.