Fears of Iranian Sleeper Cell Retaliation Grow in the West as Middle East War Escalates

Fears of Iranian-backed terrorism are intensifying across Western countries, with officials warning Iran could mobilize terrorist sleeper cells and proxy networks in revenge for the unprecedented US-Israeli strikes on Saturday that killed Supreme Leader Ayatollah Ali Khamenei — prompting governments to raise threat levels and bolster security for Jewish and Israeli communities abroad.

Sleeper cells are covert operatives or terrorists embedded in rival countries who remain dormant until they receive orders to act and carry out attacks.

As the war in the Middle East continues to spread and escalate, officials in Germany have warned of potential Iranian retaliation targeting Jewish and Israeli institutions nationwide, prompting several federal states to step up protections and issue alerts as threat concerns mount.

“Retaliatory measures — including the possible activation of Iranian sleeper cells in Europe — cannot be ruled out,” Marc Henrichmann, who chairs the parliamentary oversight committee of the intelligence services in Germany, told the local newspaper Süddeutsche Zeitung.

“The Iranian regime has repeatedly shown that it extends its use of terror beyond its own borders,” Henrichmann said. “Federal and state security authorities remain on the highest alert level and will adjust protective measures whenever necessary.”

Roman Poseck, the interior minister of the German state of Hesse, added to German outlet Die Welt that it should “be assumed that there will be an increase in the abstract threat situation, especially for Jewish, Israeli, and American institutions.”

Meanwhile, Felix Klein, the German government’s commissioner for combating antisemitism, warned to the Funke media group that, following the outbreak of conflict with Iran, “we must assume an increased threat to Jewish life in Germany.”

In France, Interior Minister Laurent Nuñez also issued a heightened alert, warning of potential threats and urging regional authorities to reinforce security around Jewish places of worship.

“In light of the current international situation in the Middle East, I reiterate my instructions to remain vigilant and ask you to immediately implement enhanced security measures for Jewish places of worship and religious gatherings,” Nuñez told French newspaper Le Figaro.

The United States and Israel carried out a series of strikes on military and leadership targets across Iran — including senior officials and Islamic Revolutionary Guard Corps commanders — after negotiations over Tehran’s nuclear and missile programs failed to yield results.

Shortly after reports emerged that the US–Israeli joint operation may have killed Khamenei, US President Donald Trump released a message urging Iranians to consider a future beyond the current regime and expressing guarded hope that the moment could lead to meaningful change.

The escalation came weeks after the Iranian regime killed tens of thousands of civilians in a sweeping crackdown on last month’s anti-government protests. The outbreak of fighting also followed last June’s 12-day war between Iran and Israel, which concluded after the US joined and bombed Iranian nuclear sites.

Beyond Europe, fears of Iranian retaliation are rising in the US, as counterterrorism agencies warn that additional resources are being rushed into efforts to detect and disrupt potential revenge attacks on American soil.

Although no specific credible threats have been publicly disclosed, FBI Director Kash Patel said Saturday that US counterterrorism and intelligence agencies were operating under heightened alert, with personnel “working 24/7 … to address and disrupt any potential threats” on US soil.

“While the military handles force protection overseas, the FBI remains at the forefront of deterring attacks here at home – and will continue to have our team work around the clock to protect Americans,” Patel wrote in a post on X.

Amid growing fears of possible retaliation, Secretary of Homeland Security Kristi Noem also said authorities are “in direct coordination with our federal intelligence and law enforcement partners as we continue to closely monitor and thwart any potential threats to the homeland.”

Concerns over the activation of Iran’s sleeper cells have surged even further after a deadly mass shooting in Austin, Texas involving a suspect with alleged support for the Islamist regime and a separate gun attack on the gym of an Iranian dissident in Richmond Hill, Ontario. Both incidents stoked fears of politically motivated violence linked to the broader regional crisis in the Middle East.

On Sunday, a gunman opened fire at a bar in Austin’s West Sixth Street district, killing two people and injuring 14 others before being shot and killed by police.

Authorities later reported finding a flag of the Islamic Republic and photographs of Iranian leaders inside the suspect’s apartment, deepening concerns about potential links between the attack and broader political or ideological influences.

According to the FBI and the Joint Terrorism Task Force, there were indicators that could suggest a possible terrorism link.

In Canada, hours after the announced death of Khamenei, a boxing gym run by Iranian-Canadian dissident activist Salar Gholami was struck by gunfire overnight.

Tehran’s ability to coordinate or inspire attacks on American soil has long been a concern for US law enforcement and intelligence officials — a fear that only deepened after Trump ordered the assassination of Iranian General Qasem Soleimani in 2020.

Amid the 12-day war in June, NBC News reported that Iran had privately warned the United States that it could activate sleeper cells on American soil in response to military action. While no specific plots were publicly disclosed, US authorities increased domestic security measures and intelligence monitoring in anticipation of possible attacks. Vice President JD Vance said the Trump administration was examining the possibility of an Iran-backed homeland attack “very closely.”