United States security agencies are examining a set of encrypted transmissions believed to have originated in Iran that may signal the activation of covert operatives outside the country, according to a federal government alert circulated to law enforcement agencies.
The alert, reviewed by ABC Newsindicates that US officials intercepted coded communications shortly after the death of Iran’s Supreme Leader Ayatollah Ali Khamenei, who was killed during a joint US-Israeli strike on February 28.The report cites analysts, claiming that the transmissions could serve as an “operational trigger” intended for clandestine recipients believed to hold the relevant encryption keys.
While authorities emphasize that no specific operational threat has yet been identified, the alert has prompted heightened vigilance among federal and local law enforcement agencies.
Encrypted transmissions raise ‘Sleeper Cell’ security concerns
According to the alert reported by abc newspreliminary signals analysis detected a transmission “likely of Iranian origin” that was rebroadcast across several countries shortly after Khamenei’s death.
The message was encoded and believed to be intended for “clandestine recipients” capable of decrypting its contents.
Officials described the communication as the type commonly used to convey instructions to covert operatives without relying on internet-based channels.
The alert stated that the transmission appeared to be designed to “impart instructions to ‘covert operatives or sleeper assets’ without the use of the internet or cellular networks.”
US authorities added that it is possible the message could “be intended to activate or provide instructions to prepositioned sleeper assets operating outside the originating country.”
The precise contents of the transmission remain unknown.
“While the exact contents of these transmissions cannot currently be determined, the sudden appearance of a new station with international rebroadcast characteristics warrants heightened situational awareness,” the alert said.
No specific threat identified, authorities say
Despite the concerns raised by the intercepted communication, US officials stressed that there is currently no confirmed operational threat tied to a specific location.
However, the alert instructs law enforcement agencies to increase surveillance of unusual radio-frequency transmissions and other signals that might indicate covert communication networks.
What are sleeper cells?
Sleeper cells are covert groups or individuals embedded within a foreign country who remain inactive for long periods until they receive instructions to carry out operations.
Such operatives often live ordinary lives while secretly maintaining allegiance to an intelligence service or militant organization. When activated, they may conduct espionage, sabotage or attacks on strategic targets.
Because sleeper cells operate quietly for extended periods without communication, they can be difficult for intelligence agencies to detect.
Encrypted broadcasts transmitted through radio signals have historically been used by intelligence organizations to communicate with such operatives, as the messages can be transmitted anonymously and intercepted only by those possessing the proper decryption keys.
War with Iran heightens global security fears
The alert comes amid escalating tensions following the US-Israeli military campaign against Iran. The killing of Ali Khamenei during the early stages of the conflict has significantly intensified geopolitical tensions across the region.
Security officials have long warned that Iran could potentially rely on covert networks or allied groups abroad to respond to such attacks.
The latest intelligence warning does not confirm that sleeper cells have been activated, but authorities say the intercepted transmissions warrant increased vigilance.
For now, US law enforcement agencies are being urged to closely monitor suspicious communications and unusual signal activity while investigators attempt to determine the true purpose of the mysterious broadcast.
