FBI ramps up surveillance of potential sleeper cells after Iranian strikes

Federal and local law enforcement agencies have also beefed up security on the ground in major US cities as part of a precautionary stance, although no specific, credible threats have been publicly identified.

The move follows Saturday morning’s operation, dubbed “Operation Epic Fury,” which resulted in the killing of Iran’s Supreme Leader Ayatollah Ali Khamenei and several senior Iranian officials in a coordinated military campaign between the United States and Israel.

Security experts warn that the repercussions may extend beyond the Middle East.

“If there was ever a Hezbollah cell or a Hamas cell behaving in a violent manner in the United States, this is it now,” Chris Swecker, a former FBI assistant director, told Fox News.

He added, “Both organizations are supported by Iran along the way. Both organizations have had a presence in the United States since the 1980s.”

Swecker said that US authorities had long been aware of the local networks and their sympathizers.

He added: “We know that they have cells here. We also know that there are individual sympathizers, and many of them have come out in these protest groups.”

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Demonstrators walk during a protest in New York City on Saturday, February 28, 2026. (Angelina Katsanis/Bloomberg via Getty Images)

He also warned that security weaknesses at the border may have exacerbated the risks.

“We have just come out of four years of open borders, and I said before that this was an open door for terrorists to terrorist cells and terrorist sympathizers to infiltrate. Many of them were already here, but there was no way they would not infiltrate these specific groups and act as catalysts, as enablers.”

Against that background, FBI It is moving to strengthen its internal security position.

FBI Director Kash Patel said on Saturday that Combating terrorism Intelligence teams are now on high alert amid ongoing US actions related to Iran.

“Last night, I instructed our counter-terrorism and intelligence teams to be on high alert and mobilize all necessary auxiliary security assets,” Patel said. books On X.

Patel added that while the U.S. military protects troops abroad, the FBI “remains at the forefront of deterring attacks here at home” and will continue to work around the clock to protect Americans.

FBI raises counterterrorism teams to high alert amid Iranian tensions

FBI Director Kash Patel stands silently during a news conference on October 23, 2025 in New York City. (Michael M. Santiago/Getty Images)

Jason Pack, a retired FBI supervisory special agent and Fox News contributor, said heightened surveillance is routine when U.S. military operations intersect with adversaries who have historically responded through indirect or unconventional means.

“The intelligence and counterterrorism communities work on these types of scenarios constantly, long before any conflict begins,” Buck said. “When the United States commits to a joint military campaign with Israel, the internal threat environment does not simply remain constant. It can change, perhaps dramatically.”

He noted that hostile actors — including Hezbollah, Hamas external networks, and Iranian Revolutionary Guard proxies — have historically demonstrated the intent and, in some cases, the ability to retaliate against U.S. military actions.

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A plume of smoke rises after an explosion on February 28, 2026, in Tehran, Iran. (Majed Saeedi/Getty Images)

Meanwhile, the Minister of Homeland Security Kristi Noem It said it was “coordinating directly with our federal intelligence and law enforcement partners as we continue to closely monitor and thwart any potential threats to the homeland.”

The heightened alert comes as parts of the Department of Homeland Security face a… Partial closureWhich raises additional questions about resources and operational pressure at a time when federal agencies are under heightened surveillance.

Although no specific plots have been identified, officials acknowledge that the threat environment could change rapidly as tensions abroad develop and whether or not that escalation reaches U.S. soil remains to be seen.

Fox News Digital’s Michael Dorgan and Kelly Kramer contributed to this report.