WATCH: Pentagon holds news briefing as classified leak suspect Jack Teixeira pleads not guilty

Pentagon press secretary Pat Ryder held a briefing on Thursday, a day after Jack Teixeira, the Massachusetts Air National Guard member accused of leaking highly classified military documents on a social media platform, pleaded not guilty to federal felony charges.

Watch the briefing in the player above.

Teixeira, 21, entered the pleas during a hearing in Worcester’s federal court days after he was indicted by a grand jury on six counts of willful retention and transmission of national defense information. Each count is punishable by up to 10 years in prison.

The leak left the Biden administration scrambling to assess and contain the damage among the international community and reassure allies that its secrets are safe with the U.S.

Teixeira’s family said in a statement Wednesday that they “remain committed as ever” to supporting him. “The important thing is Jack will now have his day in court,” they said. “We are hopeful that Jack will be getting the fair and just treatment he deserves.”

Teixeira’s attorney has said his client “will answer the charges” and “will be judged by his fellow citizens.” In pushing for his release, Teixeira’s attorneys argued that the government isn’t alleging Teixeira ever intended that the information be widely disseminated.

Teixeira is accused of sharing classified military documents about Russia’s war in Ukraine and other sensitive national security topics on Discord, a social media platform popular with people playing online games. Investigators believe he was the leader of an private chat group called Thug Shaker Central, where enthusiasts shared jokes, talked about their favorite types of guns and discussed wars, including Russia’s invasion of Ukraine.

Authorities say Teixeira, who enlisted in the Air National Guard in 2019, began around January sharing military secrets with other Discord users — first by typing out classified documents and then sharing photographs of files that bore SECRET and TOP SECRET markings. Teixeira worked as a “cyber transport systems specialist,” essentially an IT specialist responsible for military communications networks.