Some thousand demonstrators on Sunday gathered in Manhattan in solidarity with Palestinians as pro-Israel marchers counter-protested following a bloody escalation in the Middle East conflict.

The rallies followed Saturday's surge in violence that's killed hundreds and wounded thousands in the region after militant group Hamas launched a deadly assault on Israel which responded by hammering blockaded Palestinian Gaza with heavy air strikes.

Demonstrators in New York waved Palestinian flags during the peaceful march from Times Square to near both the Israeli consulate and the United Nations headquarters, where the Security Council was to convene over the weekend's violence.

"We are here in solidarity with the Palestinian people who are fighting 75 years of Israeli settler colonialism, settler violence, and 16 years of military blockade of Gaza," said Munir Atalla, a 30-year-old member of the Palestinian Youth Movement group, which was among the demonstration's organizers.

"What we saw yesterday was the people of Gaza breaking out of their open-air prison," he continued.

"It's impossible to view the events of this week, without first understanding the context that the Israeli regime is founded on violence… it's founded on the erasure and annihilation of Palestinians."

Counter-demonstration

The rally was among others backing the Palestinian cause in American cities including Washington and Chicago.

The demonstrations came as the United States quickly affirmed its support for Israel, with US President Joe Biden ordering US ships and warplanes closer to its ally and sending fresh military aid.

"Not another nickel, not another dime, no more money for Israel's crimes," protestors in New York chanted.

Sarah Barqawi, 38, told AFP she came to Sunday's rally "because my family is currently under siege in Gaza and are just waiting to know if they will be alive or dead, without any electricity, without any support, without any supplies."

"They are merely trying to defend their right to existence."

On Saturday evening the New York branches of organizations including Jewish Voice for Peace and If Not Now marched to the Brooklyn home of Chuck Schumer, the Senate's majority leader, to call "for an end to all US military funding to Israel."

Schumer was among the chorus of US political leaders over the weekend to reiterate support for Israel and its "unwavering right to defend itself."

At a separate Manhattan protest on Sunday, a couple of hundred people waving Israeli flags decried "vicious Hamas," among them Ofer Jacobawitz, who said, "We need to demonstrate for public opinion."

"We just want everyone to know that we're supporting Israel and whatever it does now in order to defend itself and prevent this from ever happening again."

New York's Governor Kathy Hochul — who lambasted Manhattan's Palestinian solidarity rally as "abhorrent and morally repugnant" — meanwhile ordered landmarks in the state including the World Trade Center and Niagara Falls to be illuminated in blue and white.

"New York is proud to be home to the largest Jewish population outside Israel," she said.

As he marched on Sunday at the Palestinian solidarity rally, Morgan Bassichis, 40, told AFP that "as a Jewish person who believes that everyone, with no exception, should be free, I am firmly in support of the Palestinian freedom movement, and I believe that all violence in the region is a result of the root cause of Israeli apartheid."

"It's our job as people in the US to get our government" to stop financing Israel, he said.