It comes as Mr Hegseth is scheduled to testify before Congress next week for the first time since his confirmation hearing. He is likely to face questions under oath not only about his handling of sensitive information but also the wider turmoil at the Pentagon following the departures of several senior aides and an internal investigation over information leaks. Mr Hegseth already has faced questions over the installation of an unsecured internet line in his office that bypassed the Pentagon’s security protocols and revelations that he shared details about the military strikes in multiple Signal chats. One of the chats included his wife and brother while the other included President Donald Trump’s top national security officials and inadvertently included The Atlantic’s editor-in-chief Jeffrey Goldberg. Neither the Pentagon nor the inspector general’s office immediately responded to Friday requests for comment on the investigation. Besides finding out whether anyone was asked to delete Signal messages, the inspector general also is asking some past and current staffers who were with Mr Hegseth on the day of the strikes who posted the information and who had access to his phone, according to the two people familiar with the investigation and the documents reviewed by the AP. Democratic lawmakers and a small number of Republicans have said that the information Mr Hegseth posted to the Signal chats before the military jets had reached their targets could have put those pilots’ lives at risk and that for any lower-ranking members of the military it would have led to their firing. Mr Hegseth has said none of the information was classified. Multiple current and former military officials have said there is no way details with that specificity, especially before a strike took place, would have been OK to share on an unsecured device. “I said repeatedly, nobody is texting war plans,” Mr Hegseth told Fox News Channel in April after reporting emerged about the chat that included his family members. “I look at war plans every day. What was shared over Signal then and now, however you characterise it, was informal, unclassified co-ordinations, for media co-ordinations and other things. That’s what I’ve said from the beginning.” Mr Trump has made clear that Mr Hegseth continues to have his support, saying during a Memorial Day speech at Arlington National Cemetery in Virginia that the defence secretary “went through a lot” but “he’s doing really well”. Mr Hegseth has limited his public engagements with the press since the Signal controversy. He has yet to hold a Pentagon press briefing and his spokesman has briefed reporters there only once. Signal is a publicly-available app that provides encrypted communications, but it can be hacked and is not approved for carrying classified information. On March 14, one day before the strikes against the Houthis, the defence department cautioned personnel about the vulnerability of the app.