By Bernd Debusmann Jr in New York and Mike Wendling, BBC News
The University of Southern California in Los Angeles has cancelled its main graduation ceremony on 10 May, citing safety measures.
The move comes amid ongoing protests against the Israel-Gaza war which have erupted at dozens of US campuses.
At Atlanta's Emory University, 28 protesters were arrested on Thursday after refusing to leave.
The spate of campus protests began at Columbia University in New York City last week.
In a statement on Thursday, USC said it "will not be able to host the main stage ceremony that traditionally brings 65,000 students, families and friends to our campus".
The decision comes after police made multiple arrests when confronting protesters at the university's campus on Wednesday and ordered the dismantling of an encampment.
It is also after USC said earlier this month that Muslim student Asna Tabassum would no longer be permitted to deliver a speech as valedictorian due to unspecified security threats.
Protests also erupted at Emory University in Atlanta, where demonstrators said they were supporting Palestinians but also voicing their objection to a police training centre in Atlanta.
Plans for the centre have been controversial locally and the project has been dubbed "Cop City" by opponents.
In a statement, Emory said that outside protesters were later joined by "members of the Emory community" and the group was "disrupting the university as our students finish classes and prepare for finals".
Police said the group "pushed past" officers protecting the area set up for commencement on Thursday morning, and that some members of the crowd threw "objects" at police.
"Due to the direct assault of officers, law enforcement released chemical irritants into the ground to assist with crowd control," Emory's police force said.
Atlanta Police also confirmed they used chemical irritants but denied reports they fired rubber bullets at protesters.
One of the protesters shown on video being detained by police identified herself as Noelle McAfee, chairperson of Emory's philosophy department.
McAfee said she was observing what she described as a peaceful protest when police began to move in and the protesters started to march.
"It went from a peaceful protest to mayhem in the matter of a minute," she said. She said she froze and quickly was detained.
The latest wave of campus protests against the war began at Columbia University in New York, after school officials called in police to clear a new protest encampment and more than 100 people were arrested.
The movement has now reached dozens of college campuses across the country.
Activists have been calling for universities to "divest from genocide" and to stop investing large school endowments in companies involved in weapons manufacturing and other industries supporting Israel's war in Gaza.
Chisato Mimura, a law student and protest leader at Yale University in Connecticut, told the BBC activists were upset at President Joe Biden as well as their school officials for "quite literally funding and equipping the weapons used in genocide".
"But instead, what they're doing is completely putting their full weight behind it," she said. "We are well aware of the prominent role they are playing."
Israel strongly denies any suggestion it is committing genocide in the Palestinian enclave, though the International Court of Justice has said the accusation was "plausible".
Some of the protests have been accused of antisemitism. A number of Jewish students have said they have felt unsafe at Columbia and at other universities, although other Jewish students have joined the demonstrations.
At Columbia, the university administration have set a Thursday midnight deadline to reach a deal with student protesters to avoid further disruption.
In a news conference, university spokesperson Ben Chang said if no agreement was reached, "we will have to consider options for restoring calm to campus", but he did not outline any specific measures that would be taken.
Chang said the university was preparing for further protests on Thursday evening.
Earlier on Thursday, Minnesota Democratic congresswoman Ilhan Omar visited the campus. Her daughter, Isra Hirsi, was one of the protesters cleared from the university by police last week.
"This is a movement that started with only 70 students," Omar told the BBC. "And because Columbia University decided to crack down on them and violate their First Amendment [rights], this has now spread nationally and internationally."
In other recent developments:
- In Syracuse, New York, Biden was greeted by about 100 protesters with signs reading "Genocide Joe" and other slogans as he attended an official event
- A camp was set up at Northwestern University near Chicago, where school officials moved to limit the use of tents. Police were on campus and ordered protesters to leave, but no arrests were reported
- Organisers of the Uncommitted movement, which has encouraged Democratic primary voters to reject Biden, said they would join the student activists camping at the University of Michigan.
- Students at Georgetown University, George Washington University and American University protested in Washington DC.
- More than 200 arrests were made on Wednesday at Emerson College in Boston; the University of Southern California (USC) in Los Angeles; and the University of Texas at Austin
- Brandeis University in Boston, where one-third of the student body is Jewish, said it would extended its transfer deadline to accommodate students who feel targeted and attacked at other schools.
The war began when Hamas-led gunmen carried out an unprecedented attack on southern Israel on 7 October, killing about 1200 people - mostly civilians - and taking 253 others back to Gaza as hostages.
More than 34,180 people - most of them children and women - have been killed in Gaza since then, the territory's Hamas-run health ministry said.
- BBC