Washington, March 5 (IANS): A Massachusetts Air National Guardsman accused of posting classified intelligence information and sensitive documents online has pleaded guilty to the crimes he was charged with, in exchange for a possible sentence of 16 years in prison.

Jack Teixeira, the airman, pleaded guilty to all six counts of "willful retention and transmission of national defense information" during an appearance at a federal court in Boston, Massachusetts, US media reported, citing court documents and the 22-year-old's remarks in court. He previously pleaded not guilty.

Judge Indira Talwani asked Teixeira during the hearing whether he understood he was agreeing to serve as many as 16 years and at least 11 years behind bars, Xinhua news agency reported, citing a report by ABC News.

"Yes your honour, I understand," Teixeira was quoted by the outlet as saying.

"How do you now plead to counts one, two, three, four, five and six? Guilty or not guilty?" the clerk asked. "Guilty," Teixeira said in response.

An announcement of Teixiera's sentence was scheduled by Talwani for September 27.

Teixeira has agreed to sit for a debrief with members of the intelligence community and the Department of Defense, and return all relevant documents either currently in his possession or he knows the location of, according to the plea agreement.

Under detention since his arrest in April 2023, Teixeira was at the centre of what was considered one of the most serious leaks of national security information in the US.

Boasting his privilege of having access to classified information, Teixeira posted to an online gaming chat group secrets including about the situation of the Russia-Ukraine conflict, such as the provision and delivery of weapons to Ukraine, as well as troop movements on both sides on the battlefield. Officials said such information may have compromised the way the US gathers intelligence.