Dressed in black T-shirts emblazoned with the words "Jews say cease fire now" and "Not in our name," the activists sat clapping and singing on the floor in the rotunda of the Cannon House Office building and held up large banners that read "Ceasefire" and "Let Gaza Live".

Capitol police said protests are not allowed inside the building and several demonstrators were arrested.

"We warned the protestors to stop demonstrating and when they did not comply we began arresting them," the US Capitol police said in a statement on X, formerly known as Twitter.

The protest was organized by the Jewish Voice for Peace, a Jewish anti-Zionist organization.

Before the sit-in, hundreds of people had gathered on the National Mall near the Capitol urging the Biden administration to call for a cease-fire.

"Biden really is the only one that has the power to pressure Israel right now and he needs to use that power to save innocent lives," Hannah Lawrence, 32, who came from the northeastern US state of Vermont.

Linda Holtzman, 71, a rabbi from Philadelphia, demanded an immediate ceasefire and urged Biden to "open your eyes."

"Look at what's happening in Gaza. Look at the devastation in Gaza," said Holtzman. "If you want to be able to live with yourself, you need to stand up and end the genocide. I demand a ceasefire right now."