The Trump administration’s national security leaders accidentally included the editor-in-chief of the Atlantic, Jeffrey Goldberg, in a chat on Signal discussing confidential plans to attack Yemen’s Houthis.

“I could not believe that the national-security leadership of the United States would communicate on Signal about imminent war plans,” Goldberg wrote of the March 15 messages, which Goldberg received two hours before the U.S. dropped its bombs.

Signal and other commercial tech platforms are not authorized for sharing sensitive information among government officials.

Goldberg first thought that he was being mislead by bad actors trying to plant a false story in the Atlantic. But a spokesperson from the National Security Council later confirmed to the Atlantic that this was an authentic message chain.

“I have never seen a breach quite like this,” Goldberg wrote.