WASHINGTON, D.C.: An elaborate impersonation scheme involving artificial intelligence targeted senior U.S. and foreign officials in June, exploiting deepfake voice technology to pose as Secretary of State Marco Rubio, according to a diplomatic cable reviewed by Reuters.

In mid-June, the perpetrator contacted three foreign ministers, a U.S. governor, and a member of Congress via the Signal messaging app, leaving AI-generated voicemails for at least two of them. In at least one case, a text invitation was also sent asking the recipient to switch to Signal for further communication.

"The actor likely aimed to manipulate targeted individuals using AI-generated text and voice messages with the goal of gaining access to information or accounts," the cable said.

The Washington Post was the first to report the attempted impersonation.

A senior State Department official, speaking on condition of anonymity, confirmed: "The State Department is aware of this incident and is currently investigating the matter."

"The Department takes seriously its responsibility to safeguard its information and continuously takes steps to improve the department's cybersecurity posture to prevent future incidents," the official added.

The cable, dated July 3, was sent to all U.S. diplomatic and consular posts, and staff were advised to warn external partners about the rise of impersonation campaigns and fake digital identities.

"There is no direct cyber threat to the department from this campaign, but information shared with a third party could be exposed if targeted individuals are compromised," the cable warned.

While the cable did not name a perpetrator, it referenced a similar incident from April involving a Russia-linked hacker. That earlier phishing campaign targeted think tanks, Eastern European activists, dissidents, and former State Department officials.

In that case, the attacker mimicked a "@state.gov" email address and used official-looking logos from the Bureau of Diplomatic Technology. "The actor demonstrated extensive knowledge of the department's naming conventions and internal documentation," the cable noted.

That campaign involved messages sent to private Gmail accounts, with industry partners later attributing it to a cyber actor affiliated with the Russian Foreign Intelligence Service.

The latest incident also follows a Wall Street Journal report revealing that U.S. federal authorities are investigating a separate attempt to impersonate White House chief of staff Susie Wiles.