By Nate Raymond and Kanishka Singh
BOSTON (Reuters) - Jack Teixeira, a member of the Massachusetts Air National Guard, is expected to plead guilty to charges related to his alleged leaking of classified military information on a social media platform in what was one of the most serious U.S. national security breaches in years, according to a court filing.
Federal prosecutors asked a judge in Boston to schedule a Monday hearing for Teixeira, 22, to change his plea following his arrest in April on charges he leaked classified documents to a group of gamers on the messaging app Discord.
The material included highly sensitive U.S. military assessments, including on the war in Ukraine.
Further information, including what charges Teixeira would plead guilty to, was not immediately available. He had been facing six counts of willful retention and transmission of classified information relating to national defense.
Lawyers for Teixeira, of North Dighton, Massachusetts, did not respond to requests for comment.
The leak was considered the worst U.S. national security breach since more than 700,000 documents, videos and diplomatic cables appeared on the WikiLeaks website in 2010.
The documents leaked on Discord included highly classified information on U.S. allies and adversaries, with details ranging from Ukraine's air defenses to Israel's Mossad spy agency.
In December, the U.S. Air Force moved to discipline 15 personnel over the leaking of classified military information allegedly by Teixeira.
An Air Force Inspector General report into the incident found that some member of Teixeria's unit and leadership "had information about as many as four separate instances of his questionable activity."
A smaller number of people had a more complete picture of his intelligence-seeking behavior and "intentionally failed to report the full details of these security concerns/incidents," the report said.
(This story has been corrected to fix the month of arrest to April, not June, in paragraph 2)