British police estimated that up to 100,000 marchers participated. The crowds, carrying Palestinian flags, also demanded that Israel discontinue deadly airstrikes in the enclave.
The Council on American-Islamic Relations canceled plans to hold its 29th annual banquet on Saturday at the Marriott Crystal Gateway in Arlington, just across the Potomac River from Washington, D.C.
President Biden has shown strong support for Israel in the wake of a deadly attack by Hamas, even traveling to the region. But it isn't making political waves in a deeply divided America.
Israel is a cornerstone of GOP foreign policy and presidential hopefuls are seeking to stand out from the crowded field as they proclaim their views on Israel, Hamas and the Middle East.
The violence marked a rare use of Israeli airpower in the territory. During the clashes, Palestinian militants detonated a roadside bomb next to an Israeli military vehicle.
Israeli Prime Minister Benjamin Netanyahu on Saturday announced a series of punitive steps against the Palestinians, including plans to beef up Jewish settlements in the occupied West Bank.
The incoming Israeli ruling coalition agreements will make it the country's most religious and right-wing government in history, potentially putting it at odds with large parts of the Israeli public.