US intelligence agencies say Iran may have sent a coded message that could activate sleeper agents overseas. Officials intercepted the encrypted transmission after the conflict involving the United States and Israel intensified.

According to a report by ABC News, the message appeared to contain a possible “operational trigger”. Such signals can instruct hidden operatives, often called sleeper assets, to prepare for action. The report said US authorities detected the encrypted communication and issued a federal alert to law enforcement agencies.

Conflict Escalates Across the Region

The warning comes as fighting between the United States, Israel and Iran continues to intensify. US and Israeli forces have carried out heavy airstrikes on Iranian targets for more than a week.

Iran has responded by launching attacks on Israel and several Gulf countries. At the same time, Israel has expanded strikes against Hezbollah in Lebanon. The Iran-backed group has continued firing rockets into Israel.

Coded Signal Sent After Khamenei’s Death

The intercepted transmission appeared shortly after the death of Ali Khamenei on February 28. US officials believe the message may contain instructions for covert operatives working outside Iran. Authorities circulated the warning through a federal memo sent to law enforcement agencies.

The memo said the signal could “be intended to activate or provide instructions to prepositioned sleeper assets operating outside the originating country.”

Encrypted Broadcast Raises Concern

Investigators said the transmission was encrypted and meant for secret recipients who possess the correct encryption key. These types of signals allow governments or intelligence networks to send instructions without using the internet or mobile communication.

US intelligence agencies said they detected a broadcast station repeatedly transmitting the message to several countries outside Iran.

“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 memo said.

Officials clarified that there is currently no confirmed operational threat linked to a specific location. However, authorities asked law enforcement agencies to monitor unusual radio-frequency signals.

Security Agencies Increase Alert Level

Counterintelligence experts have warned that the ongoing war with Iran could increase the risk of revenge attacks in the United States. Chris Swecker raised concerns about possible militant activity.

“If ever there’s going to be a Hezbollah cell or a Hamas cell act in the United States in a violent way, it’s now,” Swecker told Fox News soon after the conflict began. Following US airstrikes on Iran on February 28, Kash Patel announced increased security measures.

He wrote on X that he had ordered “counterterrorism and intelligence teams to be on high alert and mobilise all assisting security assets needed.”

Trump Warns War Could Bring Casualties

Donald Trump also addressed concerns about potential attacks on the US mainland.

“I guess ... We think about it all the time. We plan for it. But yeah, you know, we expect some things. Like I said, some people will die. When you go to war, some people will die,” Trump said.

Major US Cities Tighten Security

Authorities in several large US cities have already increased security measures.

Leaders in Los Angeles, Miami and New York City announced stronger police patrols in sensitive areas.

Officials said they are focusing on locations such as places of worship, cultural centres and schools. The move aims to prevent potential attacks and reassure local communities.