In the aftermath of the U.S. strikes on Iran, officials and lawmakers are warning of potential threats from Iranian or Iran-affiliated “sleeper cells” embedded in the United States, a threat that could persist in spite of the ceasefire reached last week.

Experts say that there is a real threat that Iran could seek to target the U.S. government, Jewish communities or other targets within the United States, either through networks of operatives in the country or individuals radicalized online against Israel and Jews.

“Though we have not received any specific credible threats to share with you all currently, the threat of sleeper cells or sympathizers acting on their own, or at the behest of Iran, has never been higher,” Customs and Border Protection Commissioner Rodney Scott said in a memo to CBP personnel earlier this month, asserting that thousands of known and unknown Iranian nationals are believed to have entered the United States.

Iran also reportedly sent a message to President Donald Trump days before the U.S. strikes on Iranian nuclear facilities, threatening to activate a terrorist network inside the United States if the U.S. struck Iran, NBC News reported.

A Department of Homeland Security public bulletin warned that the conflict in Iran could prompt attacks in the United States, and that a specific direction from Iran’s religious leadership could increase the likelihood of homegrown violent extremist mobilization. It also warned of potential cyberattacks.

Both before and after the U.S. strikes, lawmakers on both sides of the aisle had delivered similar warnings. Jewish community security groups came together to caution institutions to take heightened precautions in response to the strikes to protect their physical safety and cybersecurity.

Matthew Levitt, the director of the counterterrorism and intelligence program at The Washington Institute for Near East Policy and a former counterterrorism official, told Jewish Insider that homeland threats are very real, though he argued that the term “sleeper cells,” which he said invokes spy thriller TV shows, can trivialize the threat.

Levitt said there are past cases of Islamic Revolutionary Guard Corps-linked operatives being smuggled into the U.S. and surveying sensitive government and Jewish community locations. One such individual, after his arrest, told authorities he might have been instructed to attack those sites following a development like a direct American attack on Iran.

Levitt said that there have also been documented cases of groups such as Hezbollah setting up networks abroad to raise funds or spread propaganda, among other operations — but these individuals are generally not, as seen in popular culture, “a trigger puller who’s been sent here to wait until he’s ultimately told to pull the trigger.”

“There is real concern that if there was ever a time when Iran or Hezbollah was going to use these types of operatives, now would be it,” Levitt said, “especially since their other toolkits have generally been denied to them.”

Embedded foreign operatives operatives are likely few in number, Levitt added. A larger threat is from individuals in the United States who have been radicalized by anti-Israel and antisemitic propaganda or could be prompted to violence by a potential future Shia religious edict.

The degradation of Iran’s proxies and limited effectiveness of its missile attacks leaves “the potential for international terrorist attacks” that are less easy to definitively trace to the Iranian government, but send a message that “they haven’t been beaten” and can still retaliate, Levitt said.

Oren Segal, the vice president of the Anti-Defamation League’s Center on Extremism, told JI that “this specific conflict speaks to concerns that intelligence agencies have talked about for years, about the idea that Iran or its proxies have people around the world.”

“It’s understandable for not only the Jewish community, but frankly, the broader community, to be feeling anxiety over whether these people are in place and what they might do,” Segal continued.

He said it’s difficult to know how many direct Iranian assets might be in the United States, but regardless of that, there’s an ongoing threat of individuals being radicalized online.

“You don’t have to look too far to see attacks that have happened, or plots in this country that were motivated or animated by ideology, as opposed to somebody coming in from abroad,” Segal said. “To me, that is always going to be the most omnipresent threat.”

He emphasized that violent language targeting the Jewish community has skyrocketed since recent antisemitic terrorist attacks in Washington and Boulder, Colo., and “we just don’t have the luxury to ignore any of these threats.” 

Secure Community Network CEO Michael Masters, speaking on a recent webinar with FBI and DHS officials, warned of heightened risks to Jewish community groups that could emanate from a range of different sources, according to prepared remarks reviewed by JI.

Masters emphasized that Iran has a record of attempting operations inside the United States in recent years, and noted that U.S. military engagement against Iran has long been seen as a likely trigger for Iranian retaliatory attacks in the United States.

He said SCN believes that Jewish institutions and leaders would be top targets of Iranian proxies and criminals working with them. And he noted that within hours of the U.S. attacks on Iran, SCN had identified nearly 1,700 violent social media posts targeting the American Jewish community.

Levitt said that the “good news is” that IRGC and Hezbollah operatives in the country are likely under tight surveillance, noting that recent reporting indicates that the FBI has increased its focus on such groups in recent days.

“On the one hand, I’m sure that there are adversaries that would like to do something against America in America,” Levitt said. “It’s also a case that — there’s no such thing as 100% successful — we’re pretty good at law enforcement, intelligence and border security and all that here.” 

Many Republicans have linked the “sleeper cell” threat to increased levels of undocumented immigration during the Biden administration, a connection that Levitt largely dismissed.

“I don’t subscribe to the opinion that border security was so lax in previous administrations that all kinds of bad guys got in,” Levitt said. “More people were allowed in the country. It doesn’t mean that law enforcement wasn’t doing its job, and the actual [number of] cases we know about where bad guys were able to come into the country is very, very small.”