U.S. intelligence officials are warning law enforcement agencies to remain alert after intercepting encrypted communications believed to have originated in Iran that could signal potential activity by sleeper agents abroad.
According to a federal alert circulated to authorities and reviewed by ABC News, analysts detected transmissions that may function as “an operational trigger” for covert operatives outside Iran. The alert cites “preliminary signals analysis” indicating the communication was “likely of Iranian origin” and was rebroadcast through several countries soon after the death of Ali Khamenei, Iran’s longtime supreme leader.
Khamenei was killed in a joint U.S.-Israeli military strike on Feb. 28, an event that significantly escalated tensions between Iran and its adversaries.
Officials said the message itself was encrypted and appeared to be directed at “clandestine recipients” who possess the appropriate decryption key. Intelligence experts note that such transmissions are commonly used to communicate with covert operatives without relying on conventional internet or cellular networks that can be more easily tracked.
According to the alert, the transmissions may “be intended to activate or provide instructions to prepositioned sleeper assets operating outside the originating country.”
Authorities say the signal’s sudden appearance has raised concern among analysts monitoring foreign intelligence activity. “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.
Despite the warning, officials stressed that there is currently “no operational threat tied to a specific location.” Law enforcement agencies have nonetheless been encouraged to increase monitoring of unusual radio-frequency signals and related activity.
If intelligence assessments ultimately confirm the transmission’s purpose, it could reinforce fears voiced by U.S. and allied officials after recent military strikes on Iran—that sleeper cells positioned across Western countries could be used for retaliation.