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 (AI), 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.

The recipients of the scam messages, which were sent by text, Signal and voice mail, were not identified in the cable.

"The State Department is aware of this incident and is currently monitoring and addressing the matter," department spokesperson Tammy Bruce told reporters. "The department takes seriously its responsibility to safeguard its information and continuously take steps to improve the department's cybersecurity posture to prevent future incidents."

She declined to comment further due to "security reasons" and the ongoing investigation.

It's the latest instance of a high-level Trump administration figure targeted by an impersonator, with a similar incident revealed in May involving President Donald Trump's chief of staff, Susie Wiles. The misuse of AI to deceive people is likely to grow as the technology improves and becomes more widely available, and the FBI warned this past spring about "malicious actors" impersonating senior U.S. government officials in a text and voice messaging campaign.

The hoaxes involving Rubio had been unsuccessful and "not very sophisticated," one of the officials said. Nonetheless, the second official said the department deemed it "prudent" to advise all employees and foreign governments, particularly as efforts by foreign actors to compromise information security increase.

"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 said.