[Source: Reuters]

The U.S. Air National Guardsman accused of leaking classified documents to a small group of gamers had been posting sensitive information months earlier than previously known and to a much larger chat group, the New York Times reported on Friday, citing online postings reviewed by the newspaper.

In February 2022, soon after the invasion of Ukraine, a user profile matching that of Airman Jack Teixeira began posting secret intelligence on the Russian war effort on a previously undisclosed chat group on the social platform Discord, the newspaper reported, adding the group had about 600 members.

This chat room was publicly listed on a YouTube channel and was easily accessible, the newspaper added.

The Pentagon declined to comment on the new information reported by the New York Times.

The 21-year-old U.S. Air National Guardsman facing criminal charges for leaking top-secret military intelligence records online was arrested last week.

The New York Times said the newly discovered information posted on the larger chat group included details about Russian and Ukrainian casualties, activities of Moscow’s spy agencies and updates on aid being provided to Ukraine.

The user claimed to be posting information from the National Security Agency, the Central Intelligence Agency and other intelligence agencies, according to the New York Times.

The case is believed to be the most serious U.S. security breach since more than 700,000 documents, videos and diplomatic cables appeared on the WikiLeaks website in 2010. The Pentagon has called the leak a “deliberate, criminal act.”

The leaks did not come to light until they were reported by the New York Times in early April even though the documents were posted earlier.

Teixeira was charged with one count of violating the Espionage Act related to the unlawful copying and transmitting of sensitive defence material, and a second charge related to unlawful removal of defense material to an unauthorized location. He will likely face more charges, legal experts have said.