The U.S. State Department is investigating an incident in which an unknown individual used artificial-intelligence software to mimic Secretary of State Marco Rubio’s voice and writing style and contacted senior officials, according to a diplomatic cable seen by multiple news organizations. Beginning in mid-June, the impostor reached three foreign ministers, a U.S. governor and a member of Congress via the encrypted messaging app Signal, leaving AI-generated voice mails and text messages designed to appear authentic. The cable, dated July 3 and distributed to every U.S. embassy and consulate, warns diplomats to alert external partners about fake accounts and to verify any unexpected communications. While the document says the campaign posed no direct threat to State Department networks, it cautions that information shared with third parties could be exposed if the targets were deceived. Officials believe the actor sought access to sensitive information or online accounts. A senior State Department official said the department "takes seriously its responsibility to safeguard its information" and is working to strengthen cybersecurity defenses. The cable also cites an April 2025 spear-phishing effort attributed to Russia’s Foreign Intelligence Service and notes an FBI public advisory in May about AI-driven text and voice impersonations of U.S. government figures. The Rubio episode is the second high-profile deep-fake impersonation reported this year, following a similar attempt that targeted White House Chief of Staff Susie Wiles.