Dozens of demonstrators protesting Israel’s war in Gaza were arrested Friday at the Midtown Manhattan offices of New York’s senators, Chuck Schumer and Kirsten Gillibrand, days after they broke with many of their fellow Democrats by voting against a resolution to halt U.S. arms sales to Israel.

Pressure has mounted on Democratic lawmakers to press Israel to end its military activity in Gaza, where famine and starvation have spread in recent weeks, and allow in a flood of aid.

On Friday, more than 100 protesters, who were organized by the antiwar group Jewish Voice for Peace, chanted and banged pots and pans in the lobby of the Third Avenue building where both Mr. Schumer, the Senate minority leader, and Ms. Gillibrand have office space.

“New Yorkers are heartbroken, America is heartbroken,” said Alexa Avilés, a city councilwoman who protested on Friday. “We want an end to the war, we want peace.”

The traditional bipartisan consensus in support of Israel among American lawmakers has collapsed over the course of Israel’s nearly two-year war in Gaza, which has killed more than 60,000 people, according to Gazan officials.

Support for the war has plunged into the single digits among Democratic voters, and on Wednesday 27 Democratic senators voted to halt American weapons transfers to Israel in protest of the war and the deepening humanitarian crisis in Gaza.