Iran may have looked at carrying out a surprise drone attack on the US mainland before the war with Washington and Israel began, according to an FBI bulletin shared with law enforcement in California.
The alert said Tehran was believed to have considered launching drones from a vessel off the coast to hit unnamed targets in California if the US struck Iran.
The bulletin said authorities had no extra details on timing, method, targets or who might carry out such an attack.
The warning became public as the conflict that started on February 28 entered its second week. Iran had already responded to US and Israeli strikes with missile and drone attacks across the region.
A separate Department of Homeland Security assessment also reviewed, said Iran and groups linked to it probably pose an ongoing threat of targeted attacks inside the United States though a large scale physical attack was seen as unlikely.
Governor Gavin Newsom said the state was not aware of any immediate threat and said the response was part of routine planning for worst case scenarios.
Los Angeles Mayor Karen Bass said there was no specific or credible threat to the city. Police in Los Angeles and San Francisco said they were closely watching developments and staying in contact with state and federal authorities.
President Donald Trump also played down fears of an attack on US soil, saying the matter was under investigation.
The FBI did not comment publicly on the bulletin. The document appeared to have been issued before the fighting began and was shared through the Los Angeles Joint Regional Intelligence Center.
The bulletin does not show that an attack was about to happen or that a target had been chosen but it adds to broader concern in Washington about how Iran or groups aligned with it could respond as the war grows.
