Overnight students protesting against the Israeli war on Gaza occupied a campus building, while several others formed a human chain outside, according to videos posted on social media.

"Columbia community members took back Hamilton Hall just after midnight," student group Columbia University Apartheid Divest said in a statement.

Columbia began suspending students following almost two weeks of protests against Israel's war that has killed at least 34,535 people in Gaza, mostly women and children, according to the Gaza health ministry.

The pro-Palestinian protests have swept through higher education institutions from coast to coast, after around 100 protesters were first arrested at Columbia on April 18.

In the latest crackdown, authorities at the prestigious university in New York demanded that the protest encampment be cleared by 2:00 pm (1800 GMT) or students would face disciplinary action.

"These repulsive scare tactics mean nothing compared to the deaths of over 34,000 Palestinians," said a statement, read out by a student at a press conference after the deadline, referring to the death toll in Gaza.

"We will not move until Columbia meets our demands or... are moved by force," said the student, who would not give his name.

The demonstrators have vowed to remain at the hall until their demands are met.

Among their key demands is that the institution divests financial holdings linked to Israel.

Columbia vice-president of communications Ben Chang said the university had begun suspending students participating in the anti-war protests.

He said students had been warned they would be "placed on suspension, ineligible to complete the semester or graduate, and will be restricted from all academic, residential, and recreational spaces."

Meanwhile, at the University of Texas at Austin, police clashed with protesters Monday, including using pepper spray, and made arrests while dismantling an encampment, adding to the more than 350 people detained nationwide over the weekend.

"No encampments will be allowed," Texas Governor Greg Abbott said on social media.

"Instead, arrests are being made."

Paul Quinzi, of the Austin Lawyers Guild helping those detained, told AFP they estimated "at least 80 arrests, and they are still going."

Police pushed and shoved away protesters at the Virginia Commonwealth University (VCU) in Richmond, local television footage showed. Students said police deployed teargas and pepper spray to clear them.

VCU said in a statement on social media platform X that it had repeatedly offered opportunities for the protesters to leave, claiming that many of them were not students.

The statement added: "Those who did not were subjected to arrest and trespassing."

Protests against Israel's war on Gaza, with its high Palestinian civilian death toll, have posed a challenge to university administrators across the United States, Israel's number-one ally. Institutions that have historically prided themselves as bastions of free speech are revealing that such liberties often halt when it comes to criticizing Israel.

Footage of police in riot gear summoned at various colleges to break up rallies has been viewed around the world, recalling the protest movement that erupted during the Vietnam War.

*This story was edited by Ahram Online