Senior members of Donald Trump’s cabinet have been involved in a serious security breach while discussing secret military plans for recent US attacks on the Houthi armed group in Yemen.In an extraordinary blunder, key figures in the Trump administration – including the vice-president, JD Vance, the defence secretary Pete Hegseth, the secretary of state, Marco Rubio, and the director of national intelligence, Tulsi Gabbard – used the commercially available chat app Signal to convene and discuss plans – while also including a prominent journalist in the group.The news was met with outrage and calls for an investigation in the US, with Senate minority leader Chuck Schumer calling it “one of the most stunning breaches of military intelligence I have read about in a very, very long time”Signal is not approved by the US government for sharing sensitive information.Others in the chat included the Trump adviser Stephen Miller; Trump’s chief of staff, Susie Wiles; and the key Trump envoy Steve Witkoff.The breach was revealed in an article published on Monday by Jeffrey Goldberg, the editor of the Atlantic magazine, who discovered that he had been included in a Signal chat called “Houthi PC Small Group” and realising that 18 other members of the group included Trump cabinet members.In his account, Goldberg said that he removed sensitive material from his account, including the identity of a senior CIA officer and current operational details.The report was confirmed by Brian Hughes, a spokesperson for the national security council, who told the magazine: “This appears to be an authentic message chain, and we are reviewing how an inadvertent number was added to the chain.”Hughes added: “The thread is a demonstration of the deep and thoughtful policy coordination between senior officials. The ongoing success of the Houthi operation demonstrates that there were no threats to troops or national security.”Donald Trump told reporters at the White House that he was unaware of the inc