Jack Teixeira, the Air National Guardsman accused of leaking highly classified military documents on social media, pleaded not guilty in a Massachusetts court Wednesday to six federal charges.

Teixeira, 21, was indicted earlier this month on several counts of willful retention and transmission of classified information related to the national defense. He has been held in federal custody since his arrest in April.

The Massachusetts native stands accused of sharing classified military documents on the social media platform Discord. The documents included detailed intelligence assessments of allies and adversaries alike, including the state of the war in Ukraine.

According to prosecutors, Teixeira, a junior enlisted airman who worked within the Massachusetts Air National Guard's 102nd Intelligence Wing, began posting information about the documents online around December 2022, and photos of documents in January.

Teixeira held a top-secret security clearance, and internal Air Force memos that prosecutors highlighted in court revealed that his superiors repeatedly warned him about inappropriately accessing classified intelligence.

Lawyers for Teixeira have argued in court that their client didn't expect classified information that he posted on Discord to be further spread around the internet and have slammed prosecutors for overstating the danger that Teixeira poses to national security.