Pro-Palestinian activists targeted Jewish families leaving synagogue on Shabbat in northern London, the Daily Mail reported.
The Campaign Against Antisemitism movement stated that the families were "being targeted on their way out of synagogue" on Abbey Road in St John's Wood and that it had "received multiple reports of police having to escort congregants away in groups for their own safety."
Footage posted to social media showed men shouting at Jewish worshipers from cars while holding green flares and waving Palestinian flags.
500,000 people gathered for an anti-Israel protest on the streets of London on Saturday.
British Prime Minister Rishi Sunak criticized the timing of the demonstration, which was held on Armistice Day, when Britons mourn the fallen soldiers of World War One.
Among the chants at the rally in London was the genocidal call "From the river to the sea, Palestine will be free," an infamous call for the destruction of the State of Israel and its Jewish inhabitants between the Jordan River and the Mediterranean Sea.
80 people were arrested at the London rally.