U.S. Defense Secretary Pete Hegseth’s use of commercial messaging app Signal to discuss strikes on Yemen risked compromising sensitive information and could have put troops at risk, the Pentagon’s independent watchdog said on Thursday (December 4, 2025).

“The secretary sent nonpublic DoD information identifying the quantity and strike times of manned U.S. aircraft over hostile territory over an unapproved, unsecure network,” the Inspector General’s office said in a report, using an abbreviation for the Department of Defence.

“Using a personal cell phone to conduct official business and send nonpublic DoD information through Signal risks potential compromise of sensitive DoD information, which could cause harm to DoD personnel and mission objectives,” it said.