Former national security adviser Mike Waltz was photographed using a Signal-like messaging app during Wednesday’s Cabinet meeting, more than a month after he first came under intense scrutiny for accidentally including a journalist in a group chat that discussed military plans.

A photo published by Reuters showed the screen of Waltz’s smartphone with message threads labeled “JD Vance” and “Gabbard.” The app had a similar interface to Signal, the encrypted messenger that was at the heart of “Signalgate,” but appears to instead be an app called TeleMessage, which seemingly uses some of Signal’s encryption technology while also allowing clients to archive messages for compliance purposes.

In the photo, the app displays a prompt for the user to “verify your TM SGNL PIN.” TeleMessage uses similar phrasing on its website. A search by NBC News did not turn up any other apps that use that terminology.

On Thursday, President Donald Trump announced that he would be nominating Waltz to be the U.S. ambassador to the United Nations after being relieved from his role as national security adviser.

The image adds to ongoing concerns around how Waltz and other members of the Trump administration are communicating, and especially how they are discussing classified or sensitive information. Waltz’s apparent use of the app was first reported by 404 Media.

Even though Signal is highly regarded by cybersecurity experts, the federal government has specific systems and protocols for the transmission of sensitive information and messages. Officials are expected to use intranet systems that are almost entirely closed off from the rest of the digital world, to prevent the potential breach of information via physical theft of a compromised mobile device.