US Embassy Warns Americans to Use Caution at Jewish Sites in Britain

The US Embassy in London issued a security alert Thursday warning Americans in Britain to exercise “increased caution” around Jewish and American institutions following a recent wave of antisemitic incidents and security threats across the country.

In the advisory, the embassy cited rising “threats targeting Jewish and American institutions” in Britain and elsewhere in Europe. The alert urged Americans to “stay aware of your surroundings when visiting American or Jewish institutions, community centres, and religious sites.”

The warning came days after several attacks targeting Jewish-linked sites in London and during an ongoing British counterterrorism investigation into possible Iranian involvement. The most prominent recent incident took place April 19 at Kenton United Synagogue in northwest London, where a bottle believed to contain an accelerant was thrown through a synagogue window in what police are investigating as an alleged arson attack.

British Prime Minister Keir Starmer visited the synagogue Thursday and said he was “very worried” about reports involving possible Iranian-backed activity targeting Jewish sites in Britain.

The Kenton attack followed several other incidents in recent weeks that are now being investigated by British authorities. On March 23, four ambulances belonging to a Jewish charity organization were destroyed in an arson attack in north London. British police have since made multiple arrests tied to attacks on Jewish targets and Persian-language media organizations critical of the Iranian regime. British investigators are examining whether Iran or proxies linked to Tehran may be using local criminal networks to carry out intimidation operations inside the UK.

During his Thursday synagogue visit, Starmer said Britain would move forward with legislation to formally proscribe Iran’s IRGC, a step that Britain had previously delayed despite pressure from Jewish organizations and Iranian dissidents. “In relation to malign state actors more generally, proscription, we do need legislation in order to take necessary measures,” Starmer told the Jewish Chronicle on Thursday. “We go into a new session in a few weeks' time, and we'll bring that legislation forward.”

Britain has faced increasing criticism in recent years for not formally banning the IRGC while allies including the United States, Canada, Australia, and the European Union had already imposed bans or terror designations on the organization.

The latest attacks come as antisemitism in Britain remains near record levels. In February, the Community Security Trust (CST), which monitors antisemitic incidents in the UK, reported 3,700 antisemitic incidents during 2025, one of the highest annual totals since the organization began tracking the data.

The US Embassy advisory remained active Friday as British authorities continued investigating the recent attacks and Jewish institutions across Britain maintained heightened security measures.