U.S. authorities have intercepted encrypted messages, believed to originate from Iran, which might serve as “an operational trigger” for “sleeper assets” operating outside the country, according to a federal government alert issued to law enforcement agencies.
The alert, seen by ABC News, referenced “preliminary signals analysis” of a transmission “likely of Iranian origin” that was relayed across several nations shortly after the death of Ayatollah Ali Khamenei. Khamenei, Iran’s supreme leader, was killed in a U.S.-Israeli attack on February 28.
On March 9, 2026, security forces were deployed to guard a rally in support of Iran’s new Supreme Leader at Enghelab Square in central Tehran.
Atta Kenare/AFP via Getty Images
The intercepted transmission was encoded and appeared directed at “clandestine recipients” holding the necessary encryption key, a type of message intended to convey instructions to “covert operatives or sleeper assets” without relying on the internet or cellular networks.
It is conceivable that these transmissions could “be intended to activate or provide instructions to prepositioned sleeper assets operating outside the originating country,” the alert stated.
On March 9, 2026, a crowd holding Iranian flags protested in Tehran, Iran, advocating for Ayatollah Mojtaba Khamenei to succeed his late father, Ayatollah Ali Khamenei, as supreme leader.
Vahid Salemi/AP
“While the precise contents of these transmissions are currently undeterminable, the sudden appearance of a new station broadcasting internationally warrants heightened situational awareness,” the alert conveyed.
Although the alert carefully states there is “no operational threat linked to a specific location,” it nonetheless directs law enforcement agencies to increase their monitoring of suspicious radio-frequency activity.
If the information within this alert proves accurate, it would confirm the anxieties expressed by law enforcement officials following the U.S.-Israeli strike on Iran, concerning the potential use of sleeper cells deployed across the West for retaliatory actions.