FBI Warns Iran Could Launch Surprise Drone Attacks on the West Coast From an Offshore Vessel in War Retaliation

Two weeks into a hot war with Iran, the United States is now contending with a warning it received before the first bomb dropped: that Tehran had allegedly drawn up a plan to hit California with attack drones launched from a ship in the Pacific.

The alert, sent by the FBI to police departments across California in late February 2026 and first reported by ABC News on 11 March, has elevated already-heightened counterterrorism preparations on the West Coast to their most visible state in years.

The bulletin's exact wording makes clear the limits of what the bureau actually knows. 'We recently acquired information that as of early February 2026, Iran allegedly aspired to conduct a surprise attack using unmanned aerial vehicles from an unidentified vessel off the coast of the United States Homeland, specifically against unspecified targets in California, in the event that the US conducted strikes against Iran,' the alert states.

'We have no additional information on the timing, method, target, or perpetrators of this alleged attack.'

What the FBI Alert Says — and What It Does Not

The FBI alert, distributed through the bureau's Joint Terrorism Task Force channels, was reviewed in full by both ABC News and NewsNation. It describes intelligence acquired in early February, weeks before Operation Epic Fury, indicating Iran had contemplated using drones fired from an offshore vessel against unspecified California targets if US forces attacked Iran.

The document does not name a vessel, name a target, specify a timeline, or identify the individuals who allegedly conceived the plan.

Multiple senior officials have told other outlets that the intelligence should be read cautiously. A California-based federal law enforcement official told CBS News that the information is 'not actionable.' A source with counterterrorism experience told the Los Angeles Times that the threat 'has not been deemed credible at this time' and that the warning is cautionary rather than operational.

Intelligence officials have also pointed to a practical obstacle. Iran's naval capabilities in the Pacific have been degraded significantly since Operation Epic Fury began. A statement from US Central Command confirmed that a recent strike 'eliminated' 16 Iranian naval vessels near the Strait of Hormuz. Whether the vessel described in the FBI bulletin was among those destroyed, or whether it ever existed, remains unknown.

Operation Epic Fury and What It Has Already Triggered

To understand why the drone warning matters now, it is necessary to understand what happened on 28 February. Shortly after 02:00 local time, US and Israeli forces launched nearly 900 strikes in the first 12 hours against Iranian missile sites, air defence systems, military infrastructure, and leadership targets in Tehran, Isfahan, Qom, Karaj and Kerman.

Khamenei and dozens of other senior Iranian officials were killed. His son Mojtaba Khamenei was officially named Supreme Leader on 8 March 2026.

Iran responded immediately and at scale. By 5 March, a military source cited by Fars News Agency said Iran had fired over 500 ballistic and naval missiles and close to 2,000 drones since 28 February. Roughly 40% of those launches targeted Israel; the remaining 60% were directed at US military positions in Kuwait, Qatar, Bahrain, and the UAE.

CENTCOM added a notable data point of its own on 28 February, announcing in an official statement on X that for the first time in history, US forces used one-way attack drones modelled on Iran's own Shahed design during the operation. 'CENTCOM's Task Force Scorpion Strike — for the first time in history — is using one-way attack drones in combat during Operation Epic Fury,' the statement read. 'Low-cost drones, modeled after Iran's Shahed drones, are now delivering American-made retribution.'

Sleeper Cells, Encrypted Transmissions, and the Threat Closer to Home

The offshore drone scenario is not the only intelligence thread California authorities are managing. On 9 March 2026, ABC News reported that the US had intercepted encrypted communications believed to originate in Iran that may constitute an 'operational trigger' for sleeper assets operating outside the country. The transmission was encoded and appeared to be 'destined for clandestine recipients who possess the encryption key,' according to the alert reviewed by ABC News.

The communication style, a global broadcast of number sequences transmitted outside the internet and cellular networks, mirrors techniques historically associated with Cold War-era spy networks used to relay instructions to covert operatives.

The alert was careful to note there is 'no operational threat tied to a specific location' and that 'the exact contents of these transmissions cannot currently be determined.' It did, however, instruct law enforcement agencies to increase monitoring of suspicious radio-frequency activity and to maintain heightened situational awareness.

On 1 March, the day after Operation Epic Fury began, a gunman opened fire at a bar in Austin, Texas, killing three people and injuring more than a dozen. The gunman, identified as Ndiaga Diagne, was found to be wearing clothing bearing an Iranian flag design and 'Property of Allah.' The FBI told reporters it had identified 'indicators' of terrorism. No formal terrorism charges had been filed at the time of publication.

Whether the vessel in the FBI's bulletin is real, capable, or already sunk somewhere in the Strait of Hormuz, the warning has arrived at a moment when the gap between aspiration and capability may be the only thing standing between California and a new kind of attack.