A GAZA protest camp at the the University of California, Los Angeles, (UCLA) came under attack by supporters of Israel early today, sparking about two hours of violent struggles before riot police separated the rival groups.

Hours earlier, police entered a building at Columbia University in New York that pro-Palestinian activist were occupying and forced an end to their protest.

Protesters calling on universities to stop doing business with Israel or companies that support the war in Gaza have have set up tent camps on campuses across the country.

The ensuing police crackdown at some institutions, involving more than 1,000 arrests, has stirred echoes of the student protests against the Vietnam war.

The clashes at UCLA took place around a tent encampment built by pro-Palestinian protesters, who erected a line of parade barricades, plywood and wooden pallets at the edge of the camp while counter-protesters tried to pull them down.

People threw chairs and other objects and at one point a group piled on a person who lay on the ground, kicking and beating them with sticks until others pulled them out of the scrum.

Los Angeles Mayor Karen Bass called the violence “absolutely abhorrent and inexcusable” in a post on social media platform X. The university said it had requested help.

Police entered Columbia’s campus on Tuesday night after the university called them following “physical altercations” between rival protesters.

A tent camp was cleared, along with Hamilton Hall, where a stream of officers used a ladder to enter through a second-floor window.

Protesters had began the occupation about 20 hours earlier and the university accused them of vandalising the hall.

A few dozen people were arrested at the building after protesters defied an earlier ultimatum to abandon the encampment Monday or be suspended.

Student Fabien Lugo said he was not involved in the protests but he opposed the university’s decision to call in police, saying: “It feels like more of an escalation than a de-escalation.”

At the City College of New York, demonstrators were in a confrontation with police outside the main gate, with officers pushing some people to the ground and shoving others.

Brown University reached an agreement on Tuesday with protesters on its Rhode Island campus for their action to end in exchange for administrators taking a vote to consider divestment from Israel in October.

At Northern Arizona University in Flagstaff, police in riot gear closed in on an encampment on Tuesday night and arrested about 20 people for trespassing.

Police also cleared a protest camp at Tulane University early today.