How Likely Is An Iranian Sleeper Cell Attack On US Soil?

The U.S. strike against Iran on Saturday night has ignited fears that Iran may choose to orchestrate attacks against Americans with undercover agents.

Iran threatened to activate sleeper cells in the U.S. days before President Donald Trump decided to strike Iran’s nuclear facilities Saturday night, two U.S. officials told NBC News. In the wake of the U.S. attacks against the Iranian nuclear program, the Department of Homeland Security (DHS) issued a memo Sunday warning of a “heightened threat environment” in light of the attacks, warning that Iranian government affiliates could launch terrorist attacks.

“The likelihood of violent extremists in the Homeland independently mobilizing to violence in response to the conflict would likely increase if Iranian leadership issued a religious ruling calling for retaliatory violence against targets in the Homeland,” the memo read. “Multiple recent Homeland terrorist attacks have been motivated by anti-Semitic or anti-Israel sentiment, and the ongoing Israel-Iran conflict could contribute to U.S.-based individuals plotting additional attacks.” (RELATED: ‘Is Iran Gonna Go To The Moon?’: Marco Rubio Fires Back At CBS Host Over Her Claim About Nuke Program)

US Department of Homeland Security Secretary Kristi Noem speaks during a news conference at the Wilshire Federal Building in Los Angeles on June 12, 2025. (Photo by PATRICK T. FALLON/AFP via Getty Images)

Trump announced a ceasefire agreement on Truth Social Monday evening between Iran and Israel, set to go into effect at approximately 12:00 a.m. EST, which would mark an end to the ongoing twelve day conflict assuming it holds. While Iran may have indicated it is no longer interested in continuing the war in the short-term with the agreement, the regime has a considerable history of pursuing violent plots on American soil.

In 2011, two men linked to the Iranian government were charged in a plot to assassinate the Saudi Arabian Ambassador on American soil. One co-conspirator, Gholam Shakuri, was involved in the Iranian Revolutionary Guard Corps (IRGC) Qods Force, a key cog of Tehran’s state-sponsored terror machine.

More recently in 2024, suspected Iranian asset Farhad Shakeri was arrested in connection to an alleged plot to surveil and murder an Iranian dissident with U.S. citizenship, as well as potentially targeting Trump himself. The attack was allegedly intended to be revenge for Trump’s decision to eliminate IRGC Qods Force Gen. Qassem Soleimani in 2020.

An Iranian Intelligence operative, Majid Dastjani Farahani, was suspected by law enforcement officials of trying to target key former Trump administration officials in March 2024, including former Secretary of State Mike Pompeo.

Iranian novelist Salman Rushdie, the author of a book that some Islamic religious authorities found blasphemous and the subject of an Iranian fatwa, was stabbed in 2022 by a man with ties to Hezbollah, an Iranian proxy.

Simone Ledeen, former deputy assistant secretary of defense for the Middle East, told the Daily Caller News Foundation that Iranian networks are a cause for major concern given their history of activity in the U.S., especially after the strikes that hammered Iranian nuclear facilities over the weekend.

“I think there is a real threat and it should be taken seriously,” Ledeen told the DCNF. “We have U.S. citizens and U.S. military, those are all potential targets for these sleeper cells. But I would also take a step back and look at the attempted murders that the Iranian regime has undertaken in the last decade or so.”

Israeli Prime Minister Benjamin Netayahu has claimed that Iran attempted to assassinate Trump twice, but did not elaborate on the incidents to which he was referring. Trump said in February that he left “instructions” if he is assassinated by Iran, and that there would be “nothing left” of the Islamic Republic in the event that Tehran orchestrates his assassination, according to The Associated Press.

Lax border enforcement under former President Joe Biden allowed hundreds of Iranian nationals to enter the U.S. without much or any vetting, raising concerns that individuals on missions from Tehran could still be present in the U.S. The Biden administration apprehended 1,504 Iranian nationals at the southern border, releasing 729 into the U.S. between fiscal years 2021 to 2024.

“I’m sure the FBI is all over it, but they can’t always be everywhere, so people should feel alert,” Ledeen told the DCNF.

The U.S. dropped a number of bunker buster bombs on three Iranian nuclear sites in a daring attack on Saturday night, with initial damage assessments reportedly showing considerable damage to the Fordow, Natanz and Esfahan sites in central Iran. In response, Tehran has considered blocking the Strait of Hormuz, a vital shipping vein for the global oil supply.

Iran also launched a missile attack against a U.S. air base in Qatar Monday, with no rockets landing on target or any casualties reported. Trump noted in a Monday post to Truth Social that the Iranian regime effectively notified Washington of the attacks in advance.

Trump is hopeful that the Iranians will pursue peace after the ineffectual strike, saying in the same Monday Truth Social Post that he would “enthusiastically” encourage peace between Iran and Israel.

The Iranian Ministry of Foreign Affairs could not be reached for comment.

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