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 Huthi rebels.

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

They will also review "compliance with classification and records retention requirements," it said.

The investigation came in response to a request from the top two members of the Senate Armed Services Committee, a Republican and a Democrat, the memo said.

The Atlantic magazine revealed last week that its editor-in-chief Jeffrey Goldberg was inadvertently included in the Signal chat in which officials including Hegseth and National Security Advisor Mike Waltz discussed the strikes.

The magazine initially withheld the details the officials discussed, but later published them after the White House insisted that no classified information was shared and attacked Goldberg as a liar.

- Strike timing, intelligence info -

The chat included messages in which Hegseth revealed the timing of strikes hours before they happened and information on aircraft and missiles involved, while Waltz sent real-time intelligence on the aftermath of the military action.

The White House and a string of officials involved in the chat -- including Hegseth -- have tried to downplay the story, and Press Secretary Karoline Leavitt told journalists this week that "the case is closed."

A US judge ordered the Trump administration last week to preserve all Signal communication between March 11 and March 15.

The dates cover the period between when Waltz set up the chat -- and mistakenly added Goldberg -- and the day of deadly US air strikes on the Iran-backed Huthis.

The Atlantic said that Waltz had set some of the Signal messages to disappear after one week, and others after four, saying it raised questions about whether federal records law was violated.

Trump has largely pinned the blame on Waltz, but has also dismissed calls by Democrats for top officials to resign and insisted instead on what he called the success of the raids on the Yemeni rebels.

The Huthis began targeting shipping in the Red Sea and Gulf of Aden after the Gaza war began in 2023, claiming solidarity with Palestinians.

Huthi attacks have prevented ships from passing through the Suez Canal, a vital route that normally carries about 12 percent of world shipping traffic, forcing many companies into a costly detour around southern Africa.

The United States first began conducting strikes in response under the Biden administration, and US forces have continued to hammer the Huthis with near-daily air assaults since March 15.