(Washington) The investigation into the leak of confidential American documents is progressing, President Joe Biden said Thursday, as details emerge in the media about the profile of the suspect, who is believed to be a young member of the Air National Guard.

“There’s a full investigation going on, as you know, between intelligence and the Department of Justice, and they’re getting closer” to completion, Joe Biden said during a visit to Ireland.

The US Department of Justice has opened a criminal investigation after the documents leaked online, which detail Washington’s views on the war in Ukraine and appear to indicate intelligence gathering on close US allies.

“I’m concerned this has happened,” Joe Biden said, not sounding the alarm.

Ahead of any announcement from US authorities, the Washington Post reported on Wednesday that the leak was the work of a young man who worked on a military base, who shared his information on a private online group on the social network Discord.

The New York Times, for its part, put forward the name of Jack Teixeira, 21, a member of the intelligence department of the Massachusetts Air National Guard.

According to the daily, a certain amount of evidence points to him as the leader of the group and responsible for the leaks.

According to the Wall Street Journal, which also indicates that the perpetrator is a member of the Air National Guard, an arrest could take place as early as Thursday.

Under the pseudonym “OG”, the suspect is said to have published documents from the military base where he works for months.

“OG” had asked other members of the group not to distribute the documents, saying he had no intention of being a whistleblower, the Washington Post quoted one of its sources as saying.

He was critical of the state – whose “abuse of power” he denounced – law enforcement and the intelligence community.

The group, made up of around twenty people, was formed in 2020 around their mutual passion for firearms, military equipment and religion.

White House spokeswoman Karine Jean-Pierre said the United States was examining the “implications” of the leak “for national security.”

The Pentagon has also decided to further restrict access to this type of sensitive information, Karine Jean-Pierre told the press on the sidelines of Joe Biden’s trip to Ireland.

The spokeswoman added that the US government wants social networks to “avoid facilitating” the distribution of such confidential materials, believing that they have “a responsibility to their users and to the country.”

A spokesperson for Discord told AFP that the safety of its users was the platform’s priority and that any content violating its rules could lead to the exclusion of the offender, the closure of discussion groups, and a report to the authorities.

The company also said it is cooperating with law enforcement regarding the leaks.

The documents posted online reveal in particular the concerns of the American intelligence services about the viability of a Ukrainian counter-offensive against Russian forces.

A document reviewed by AFP also noted US concerns about Ukraine’s ability to continue to defend against Russian strikes.

Dozens of photos of these documents have been relayed on Twitter, Telegram or Discord in recent days, some having undoubtedly circulated on the internet for weeks, if not months, before attracting the attention of the press.

However, US authorities have not publicly confirmed the authenticity of these documents posted online, and it has not yet been independently verified.

Many of these documents are no longer available on the sites where they originally appeared, and US authorities are reportedly working to have them all removed.