According to sources with knowledge of the situation, US Defence Secretary Pete Hegseth formed a Signal group chat, in which he disseminated information regarding a military airstrike that occurred in March targeting Houthi militants in Yemen. Those included in the group chat reportedly consisted of individuals such as his wife and brother.
Source: https://www.euronews.com/2025/04/21/pete-hegseth-shared-details-of-yemen-strike-in-second-signal-chat-media-report