The actor, who is best known for playing Jules Vaughn in the hit HBO series, joined more than 100 demonstrators who gathered in the lobby of NBCUniversal headquarters at 30 Rockefeller Plaza on Monday to call for a ceasefire in the Israel-Hamas war, organisers confirmed on Wednesday.

The 25-year-old was among dozens of protesters detained, they said, while US President Joe Biden was filming his TV appearance on Late Night With Seth Meyers.

Schafer was pictured wearing a black t-shirt that read "Ceasefire Now" while being escorted out of the building by police.

Other protesters wore t-shirts with similar slogans while chanting "Let Gaza Live" as President Biden's motorcade pulled into the area, footage showed.

Schafer, who like many protesters also wore a face mask, was seen at one point seated on the floor as others held up a banner reading: "Jews to Biden: Stop Arming Genocide."

Jewish Voice for Peace NYC, organisers of the protest, said Schafer did attend the demonstration, and she and others are due in court next month.

"Hunter was arrested at the protest, along with 50 other people," the group said in a statement to Sky's US partner network NBC News.

"We commend her commitment to Palestinian freedom and to a future of justice for everyone."

Police said 30 people were taken into custody and issued summons for trespassing and disorderly conduct.

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Mr Biden on Monday said he hoped a ceasefire between Israel and Hamas could be secured by the end of the weekend.

Negotiations are under way for a weeks-long ceasefire to allow for the release of hostages being held in Gaza by the militant group in return for Israel releasing hundreds of Palestinian prisoners.

Despite the president's optimism, a spokesperson for Hamas told Sky News on Tuesday it was "wishful thinking".

Basem Naim refuted the president's comment, telling Sky News that Hamas would not agree to a deal without an absolute ceasefire.

"There are still gaps between what we are calling for, what we are demanding, and what is proposed from the other parties," he said.