Republican US presidential candidate Donald Trump said on Wednesday it "was a beautiful thing to watch" New York police officers raiding a Columbia University building occupied by pro-Palestinian students, and called on officials to crack down on campus protests across the United States.

"New York was under siege last night," Trump told supporters at a campaign rally in Wisconsin, praising the police officers for arresting about 300 protesters at Columbia and City College of New York who he referred to as "raging lunatics and Hamas sympathizers."

While what the student protesters are seeking varies school to school, many are demanding for an immediate ceasefire in the war on Gaza and that their universities divest from companies with military ties to Israel.

Trump comments addressed the spread of student protests against the war in Gaza across the US in recent days, seeking to capitalize on concern over campus unrest.

Republican lawmakers have accused some university administrators of ignoring antisemitic rhetoric and harassment. Many student organizers say they are peaceful and have widely disavowed violence against pro-Israel counter-protesters, although some Jewish students have said they feel unsafe on campus and unnerved by chants they say are antisemitic.

"I say remove the encampments immediately, vanquish the radicals and take back our campuses for all of the normal students who want a safe place from which to learn," Trump said.

The October 7 attack on southern Israel by Hamas militants from the Gaza Strip and the ensuing Israeli offensive on the Palestinian enclave have unleashed the biggest outpouring of US student activism since anti-racism protests in 2020.

The police response at Columbia has triggered condemnations from some Columbia faculty.

Last week, the Columbia University Senate approved a resolution saying the school's administration had undermined academic freedom and disregarded the rights of students and faculty by calling in the police and shutting down protests.

Trump sought to pin the blame for the turmoil on Democratic President Joe Biden, whose aides have condemned physical intimidation and antisemitism, while speaking out in support of peaceful protests, which have advocated for humanitarian aid in Gaza and university divestment from companies supporting the Israeli military.