A string of arson attacks targeting Jewish institutions across northwest London has been claimed by a little-known Islamist terror group with suspected ties to Iran, according to Sunday reports, as counter-terrorism police launched a widened investigation and communal security organizations urged heightened alertness throughout the Jewish community.

The Metropolitan Police said Sunday that counter-terrorism officers are probing fires at shuls and other sites linked to the Jewish community, as well as an attack on a Persian-language media company. In the most serious incident, four ambulances belonging to Hatzolah, the volunteer-led Jewish emergency medical service, were torched on March 23 in the Golders Green neighborhood.

The attacks have been claimed online by a group calling itself Harakat Ashab al-Yamin al-Islamia – rendered in English as the Islamic Movement of the Companions of the Right – commonly known as HAYI. The group emerged in March 2026 in the wake of the outbreak of the Iran war, and has taken credit for attacks against Jewish, Israeli, and Western targets it characterizes as “Zionist interests.”

In the most recent incident, in the early hours of Sunday, a bottle containing an accelerant was thrown through the window of Kenton United Synagogue in Harrow, causing smoke damage to a room inside. Video appearing to originate from HAYI shows a figure in dark clothing lighting an object and hurling it at the shul before fleeing the scene. No injuries were reported.

The Kenton attack marked the fifth incident attributed to HAYI in less than four weeks. Earlier incidents include an attempted arson attack on a Jewish temple in Finchley on April 15, an arson the same week at the former offices of the Jewish Futures educational organization in Hendon, and the torching of the four Hatzolah ambulances in Golders Green in late March. A burning object was also thrown at the offices of Iran International, a Persian-language broadcaster critical of Tehran’s government.

British police are examining whether HAYI is a front for Iran’s security services. A British security source described the string of attacks as amounting to “psychological warfare” against Jews. Metropolitan Police Deputy Commissioner Matt Jukes warned that any “thugs for hire” who carried out such attacks would face justice.

Israeli officials have characterized HAYI as a recently founded Iranian proxy. However, European authorities and independent analysts have questioned its authenticity, citing internal inconsistencies and a lack of evidence linking the group to any state or organized network. According to the Wall Street Journal, European authorities suspect that HAYI may be a fictitious entity created by Iran to claim credit for attacks orchestrated by Iranian intelligence, providing Tehran with plausible deniability and confusing investigators. Security experts cautioned that HAYI is likely a flag of convenience rather than a coherent organization, and that its claims should be treated carefully.

The Metropolitan Police has deployed extra uniformed and plainclothes officers to northwest London, along with armed response vehicles and counter-terrorism resources. Shomrim London North & East, the volunteer community patrol organization, announced Sunday evening that it has substantially increased its patrols across Stamford Hill, with enhanced coverage around shuls, schools, and communal locations. The organization’s 24/7 control room remains fully operational.

While noting that there is currently no intelligence indicating any specific threat to Stamford Hill, Shomrim urged community members to remain alert and take practical precautions. These include keeping shul entrance doors closed, refraining from posting zmanim notices outside shul entrances, being attentive to unfamiliar individuals near communal buildings, and reporting any suspicious activity immediately rather than assuming others will do so. Shomrim’s round-the-clock emergency line can be reached at 0300 999 0123.

The Community Security Trust similarly urged all Jewish institutions to strictly adhere to their security protocols in light of the attacks.

Community leaders responded with alarm. Chief Rabbi Ephraim Mirvis stated that a sustained campaign of violence and intimidation against British Jewry is gathering momentum, and warned that the country cannot afford to wait for lives to be lost before recognizing how dangerous the current moment is.

Prime Minister Keir Starmer said he was appalled by the attacks and pledged that those responsible will be found and brought to justice, adding that attacks on the Jewish community are attacks on Britain as a whole.

Britain’s MI5 domestic intelligence service has reported that more than 20 potentially lethal Iran-backed plots were disrupted in the year through last October. The group has also claimed responsibility for synagogue attacks in Belgium and the Netherlands since the start of the Iran war.