The State Department is warning U.S. diplomats of attempts to impersonate Secretary of State Marco Rubio and possibly other officials using technology driven by artificial intelligence, according to two senior officials and a cable sent last week to all embassies and consulates. The warning came after the department discovered that an impostor posing as Rubio had attempted to reach out to at least three foreign ministers, a U.S. senator and a governor, according to the July 3 cable, which was first reported by The Washington Post. “The State Department is aware of this incident and is currently investigating the matter,” it said.