Pentagon watchdog to probe US Defence Secretary Hegseth's use of Signal app to convey Houthi strike plans

U.S. Secretary of Defense Pete Hegseth. (File photo/AP)

The Pentagon inspector general's office will investigate US Defence Secretary Pete Hegseth's use of commercial messaging app Signal to discuss air strikes against Houthi militants in Yemen, a memo released on Thursday said, according to news agency AFP.

The review will also look at other defense officials’ use of the publicly available encrypted app, which is not able to handle classified material and is not part of the Defense Department’s secure communications network, AP reported.

President Donald Trump's administration is facing a scandal over the accidental leak of a group chat by senior security officials on the strikes, which targeted Yemen's Houthi rebels in a bid to curb their attacks on commercial shipping and military vessels in the Red Sea and Gulf of Aden.

Hegseth’s use of the Signal app came to light when a journalist, Jeffrey Goldberg of The Atlantic, was inadvertently added to a text chain by national security adviser Mike Waltz. The chain included Hegseth, Vice President JD Vance, Secretary of State Marco Rubio, Director of National Intelligence Tulsi Gabbard and others, brought together to discuss March 15 military operations against the Iran-backed Houthis.

The probe will evaluate "the extent to which the Secretary of Defence and other DoD personnel complied with DoD policies and procedures for the use of a commercial messaging application for official business," said the memo from the acting inspector general, Steven Stebbins, AFP reported.

"Additionally, we will review compliance with classification and records retention requirements," according to the memo. The review was launched at the request of Sen. Roger Wicker, R-Miss., chairman of the Senate Armed Services Committee, and Rhode Island Sen. Jack Reed, the committee’s top Democrat.

Hegseth and other members of the Trump administration are required by law to archive their official conversations, and it is not clear if copies of the discussions were forwarded to an official email so they could be permanently captured for federal records keeping.

In the text chain, Hegseth provided the exact timings of warplane launches and when bombs would drop — before the men and women carrying out those attacks on behalf of the United States were airborne.

Both current and former military officials have said the level of detail Hegseth shared on Signal most likely would have been classified. The Trump administration has insisted no classified information was shared.

Waltz is fighting back against calls for his ouster and, so far, Trump has said he stands by his national security adviser, AP reported.