The head of Britain’s domestic security service, MI5, raised concerns Tuesday about escalating threats from Iran, which he said has intensified its attacks against Jewish communities and military targets amid rising tensions between the two countries. Ken McCallum, MI5’s director general, delivered the annual threat assessment in London, highlighting a surge in arson and sabotage incidents targeting Jewish sites across the UK and Europe that he attributed to Iranian operatives.

McCallum noted that Iranian efforts have grown bolder, aiming at “harder targets” such as military installations. This shift has heightened alarm following a recent incident near RAF Fairford, a southern England air base used by the United States for its operations related to the ongoing conflict with Iran. The base became the focus of a security operation after five men were detained near the site in connection with suspected terrorism and explosives offenses. Although police only discovered gasoline in the vehicles involved, officials believe the attempt may have been a botched arson attack linked to Iran.

In the past year, British authorities have arrested more than 50 individuals linked to Iranian operations within the UK. Among these is a recent case involving two Iranian nationals charged over a suspected attack on Jewish targets in Manchester. Prime Minister Andy Burnham characterized the plot against RAF Fairford as “almost certainly” orchestrated by Iran’s Islamic Revolutionary Guard Corps (IRGC), the country’s elite security force. Burnham pledged a robust response to these threats, including reinforcing counterterrorism measures and expanding sanctions aimed at restricting Iran and the IRGC’s ability to operate within Britain.

As part of this intensified effort, the British government on Monday imposed sanctions on two Iranian individuals identified as key facilitators of overseas operations: Ruhollah Bazghandi, head of the IRGC’s counterespionage unit, and Shahram Ali Reza Tamarzadeh Jakki, linked to an Iranian criminal network targeting dissidents abroad. British officials have emphasized the role of such criminal proxies in executing Iran’s campaign of intimidation and violence.

The United States subsequently withdrew its bombers from RAF Fairford following intelligence about a potential Iranian drone strike, although some British security experts have questioned Iran’s technological capabilities to carry out a sophisticated drone attack on UK soil. McCallum expressed skepticism about this threat level, referencing recent incidents that showed a more limited operational capacity.

Alongside Iran, McCallum pointed to other significant threats confronting the UK, including Russia, which he described as “aggressor No. 1,” conducting hybrid attacks aimed at undermining European support for Ukraine. He also cited emerging challenges from artificial intelligence and the activities of China.

Iran has denied involvement in the attacks near RAF Fairford and other incidents in Europe. However, British authorities continue to link these operations to Iranian proxies, including Kataib Hezbollah, a group designated as terrorist by the United States and aligned with Tehran’s Revolutionary Guard. The growing hostility underscores a deteriorating security environment marked by proxy conflicts and covert campaigns targeting allied nations and vulnerable communities within Europe.