US Defense Secretary Pete Hegseth used the encrypted messaging app Signal far more extensively for official Pentagon business than previously known, The Wall Street Journal reported, citing individuals familiar with his management practices.

At least a dozen separate chat groups were reportedly used by Hegseth, often to communicate sensitive but unclassified information related to his daily duties.

In one instance, Hegseth directed aides via Signal to notify foreign governments about a developing military operation. The former Fox News host reportedly initiated many of these chats personally, sending messages from both his unsecured Pentagon office line and his personal phone.

Sensitive information shared outside official channels

Sources indicate that some of the most sensitive messages included instructions to alert foreign allies about upcoming US military actions. These communications were not made through official Department of Defense channels but instead via the Signal app.

One message regarding a planned US strike in Yemen was posted by Marine Col. Ricky Buria, Hegseth’s military aide, into a Signal chat group that included the secretary’s wife, brother, and private lawyer. Buria, who had access to Hegseth’s personal phone, routinely posted messages on the secretary’s behalf.

Hegseth’s use of Signal extended beyond official personnel. Family members and non-government individuals were included in chat groups where information related to US military operations, such as deployment of F-18s, MQ-9 Reaper drones, and Tomahawk missiles, was shared. These details were later confirmed through a transcript released by The Atlantic.

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Legal and security implications of Signal use

The Pentagon Inspector General, Steven Stebbins, launched an investigation last month into Hegseth’s Signal use following public disclosures about his communications. The inquiry is focused not only on chats involving senior officials but also on messages that may have violated laws on federal record-keeping and unclassified information handling.

A 2023 Pentagon directive prohibits the use of nongovernmental apps like Signal for official communication unless specifically authorized. Despite this, sources say Hegseth often bypassed the Pentagon’s secure networks in favor of Signal, which introduced logistical challenges for his aides and raised concerns over national security vulnerabilities.

“The use of personal phones and commercial apps introduces unnecessary risk,” said Marc Polymeropoulos, a former senior US intelligence officer. “Signal is considered unclassified by the government for a reason.”

Some messages reportedly disappeared without proper archival, raising questions about potential violations of federal record laws.

Trump administration's response and fallout

Trump defended Hegseth, telling NBC’s Meet the Press that the Defense Secretary’s job was "totally safe" and praising his performance. However, fallout from the Signal app controversy has already affected others in the administration.

National Security Advisor Mike Waltz, who mistakenly added a journalist to a Signal group discussing US operations in Yemen, has been nominated to serve as ambassador to the United Nations. Waltz is expected to face questions during his Senate confirmation over his and Hegseth’s roles in the episode.

Legal experts say the situation remains murky. Aram Gavoor, a national security law professor at George Washington University, noted that the Pentagon’s memo alone may not definitively determine the legality of Hegseth’s Signal use.

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