“Support the victims, stop the oppression,” Ahmad said, describing the violence committed by the Israeli military against Palestinians as “genocide”.

The protesters were angered by six days of violence that have left at least 145 Palestinians dead in Gaza and 10 dead on the Israeli side.

Hours before the marches, Israel had stepped up its assault on Gaza, killing a family of 10 in a refugee camp and flattening a building that house the offices of Al Jazeera and The Associated Press.

Israeli and Palestinian leaders showed no sign of backing down, however, with Israeli Prime Minister Benjamin Netanyahu pledging to continue the offensive on Gaza for “as long as necessary”, while Hamas leader Ismail Haniya said, “the resistance will not give in.”

The marches in the US also coincided with Nakba Day, or what the Palestinians call the Catastrophe, which commemorates the displacement of hundreds of thousands of Palestinians amid Israel’s declaration of independence in 1948.

In San Francisco, a raucous crowd banged drums and yelled “Palestine will be free”, while similar scenes played out in Boston as protesters walked to the Israeli Consulate for New England, blocking traffic.

Footage on social media showed protesters unfurl a banner in the colours of the Palestinian flag with the words “Free Palestine” while standing on top of the awning of the building where the consulate is located.

In Washington, DC, thousands of protesters streamed from the Washington Monument and to the National Archives, while in the city of Philadelphia, demonstrators filled Rittenhouse Square to decry US support for Israel.

A speaker at a rally in the city of Pittsburgh, meanwhile, called on US legislators to put restrictions on how Israel can spend aid from Washington.

Al Jazeera’s John Hendren, reporting from Washington, DC, described Saturday’s rallies in support of the Palestinian cause as “unusually large”.

“The protesters wanted the US government to exert more pressure on Israel, to end this conflict,” Hendren said.

“There was a real sense of dissatisfaction that the Biden administration’s policies are really not significantly different than the policies of the Trump administration or any other US administration over the past several years.”

Amid the violence, Biden on Saturday telephoned Netanyahu and reaffirmed his “strong support for Israel’s right to defend itself against rocket attacks from Hamas and other terrorist groups in Gaza”.

The US leader also spoke to Palestinian Authority President Abbas and “conveyed a commitment to strengthening the US-Palestinian partnership,” the White House added in a tweet.

Phyllis Bennis, a political analyst at the US-based Institute for Policy Studies, expressed concern about Biden’s failure to “put any pressure on Israel to stop this slaughter in Gaza”.

“This is a very familiar situation in which it appears the US is taking the lead from Israel on when they are ready for a ceasefire. And Netanyahu has made clear he is not ready for a ceasefire,” she told Al Jazeera.

The US policy, therefore, she said was “quite dangerous”.