A day before President Trump removed him from his job as national security adviser, Michael Waltz checked his phone during a White House cabinet meeting — perhaps forgetting that there were cameras in the room.
A photographer for Reuters captured the moment on Wednesday, with Mr. Waltz seen from the side, seated with other suited officials around a table. When zoomed in, the photograph clearly shows what was on his phone screen: a list of his conversations on what appears to be a modified version of the messaging app Signal.
The contents of the screen indicate that Mr. Waltz had been in conversation with several top Trump administration officials: Vice President JD Vance; Tulsi Gabbard, the national intelligence director; Steve Witkoff, the special envoy to the Middle East; and Marco Rubio, the secretary of state, who was announced as Mr. Waltz’s interim replacement on Thursday. Snippets of some messages are visible.
Mr. Waltz appeared to be using a modified version of Signal sold by TeleMessage that retains copies of messages to comply with government rules around preserving records. The screen shows a request for him to verify his “TM SGNL PIN.” Time stamps indicate that the communications were as recent as the morning of the cabinet meeting.
In response to reports of the photo, Steven Cheung, the White House communications director, said in a post on X that “Signal is an approved app that is loaded onto our government phones.” Smarsh, the Portland company that owns TeleMessage, did not immediately respond to a request for comment.
Still, the moment prompted more questions over the handling of potentially sensitive information by a top security official. Mr. Waltz has been under scrutiny since the revelation in March that he accidentally included a journalist when he set up a group chat on Signal to discuss details of a military operation in Yemen.
Democrats at the time called for the resignations of Mr. Waltz and Pete Hegseth, the defense secretary, citing the recklessness of discussing sensitive defense information outside secure government channels.
Aides have said that President Trump did not want to be seen as giving in to the news media by firing Mr. Waltz at the time. On Thursday, the president removed Mr. Waltz from his security role and nominated him to be ambassador to the United Nations.
Mr. Trump has discouraged his staff from using Signal, which encrypts messages but is not approved for sensitive government communications. “I think we learned: Maybe don’t use Signal, OK?” he said in an interview with The Atlantic last month. “I would frankly tell these people not to use Signal, although it’s been used by a lot of people.”
Earlier, he downplayed concerns over the Signal leak, and dismissed concerns over sharing attack plans on the app as a “waste of time.”