The U.S. Air Force moved to discipline 15 personnel over the leaking of classified military information allegedly by Air National Guardsman Jack Teixeira, the military said on December 11. Prosecutors say Teixeira, who was 21 at the time of his arrest in June, leaked classified documents to a group of gamers on the messaging app Discord. The classified material included highly sensitive U.S. military assessments, including on the war in Ukraine. The leak is considered the most serious U.S. national security breach since more than 700,000 documents, videos, and diplomatic cables appeared on the WikiLeaks website in 2010.