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 ...

An investigation into interim U.S. Attorney Lindsey Halligan’s reported use of the encrypted messaging app Signal to communicate with a journalist has been launched by Washington-based ethics watchdog ...

A messaging service used by former National Security Advisor Mike Waltz has temporarily shut down while the company investigates an apparent hack. The messaging app is used to access and archive ...

Defense Secretary Pete Hegseth shared details about impending U.S. airstrikes in Yemen with a private Signal group that included his wife, brother and personal attorney, according to sources familiar ...

A federal judge in Washington, D.C., has issued a preliminary injunction ordering top national security officials who discussed military operations on the encrypted messaging service Signal to notify ...