The US has reportedly intercepted encrypted communications believed to have originated from Iran and meant for clandestine recipients, ABC News reported. The message asks for the activation of sleeper cells outside the country, according to a federal government alert sent to law enforcement agencies.

The alert cited preliminary signals analysis of a transmission likely of Iranian origin, which was relayed across multiple countries. The alert originated shortly after the death of former Iranian Supreme Leader Ayatollah Khamenei on February 28. The message was transmitted without the use of the internet or cellular networks. It was meant for those who have the encryption key. "The intercepted transmission was encoded and appeared to be destined for 'clandestine recipients' who possess the encryption key, the kind of message intended to impart instructions to 'covert operatives or sleeper assets' without the use of the internet or cellular networks," ABC News reported.

The federal government alert said it's possible the transmissions could be intended to activate or provide instructions to prepositioned sleeper assets operating outside the originating country."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.

The government alert said there is no operational threat tied to a specific location but it instructed law enfrocement agencies to increase their monitoring of suspicious radio-frequency activity. At least two major terrorist attacks took place in the US after Khamenei was eliminated. A day after the war began, Ndiaga Diagne, 53, of Senegal, opened fire at a packed Austin bar, killing three people and injuring 14 others. Investigators are probing whether Diagne was motivated by the war in Iran since the suspect was wearing a shirt with an Iranian flag design on it under a hoodie printed with “Property of Allah.”Suspicious devices were ignited Saturday during protests outside Gracie Mansion, the official residence of NYC mayor Zohran Mamdani. Two men, Emir Balat and Ibrahim Kayumi, were charged for attempting to support ISIS.