Iranian Sleeper Cells In The US Activated? Encrypted Broadcasts Detected

US intelligence agencies have intercepted mysterious encrypted radio transmissions believed to have originated from Iran. The signals have reportedly raised fears of potential activation of covert operatives or “sleeper assets” overseas, particularly in the US. 

US agencies detected an encrypted broadcast shortly after the February 28 assassination of Iran's Supreme Leader Ayatollah Ali Khamenei in joint US-Israeli strikes, as per a federal alert reviewed by ABC News. The message, sent across several countries, may have been meant to activate secret operatives with a special code.

Officials say the “operational trigger” resembled broadcasts from so-called “number stations”, eerie shortwave transmissions that read out strings of numbers.

Historically used by intelligence agencies (CIA and KGB) during the Cold War, such signals can only be decoded by undercover operatives with the correct code.

The alert said that the encrypted message appeared intended for “covert operatives or sleeper assets” operating outside the originating country. Law enforcement agencies have been advised to monitor suspicious radio-frequency activity. 

Speaking to reporters last week, US President Donald Trump said there might be Iranian sleeper cells embedded in the US. “We know where most of them are. We got our eye on all of them, I think,” he said.

Security officials warn that retaliation, if attempted, could take several forms, from sleeper cells and proxy groups to lone-wolf attackers inspired by the ongoing war on Iran, as per The LA Times. Cyberattacks are also considered a potential threat, with Iranian-linked hackers previously probing vulnerabilities in American infrastructure and public utilities.

Authorities in California, home to the largest Iranian community outside Iran, have said they remain on high alert for potential lone-wolf activity.

Horace Frank, former head of counterterrorism for the LAPD, told LA Times, “Sleeper cells have always been a concern when it comes to Iranians and their proxies… their proxies are feeling a lot more desperate.”

Some experts say fears of Iranian sleeper cells in the US may be overblown. Reuel Marc Gerecht, a former CIA officer, told Fortune the idea was “probably a bit dated,” adding, “If sleeper cells existed, they would have been activated in the past.”

He said Iran is more likely to use criminal networks to target dissidents, citing the 2022 attempted murder of activist Masih Alinejad in Brooklyn.

Michael Rubin, a former Pentagon official, said, “We don't need to worry about deep-cover Iranian sleeper cells like you might see in Hollywood. When the Iranians operate in the US, they often operate by tapping into existing criminal networks.”