The office of California's governor has criticised the police response to violence on campus at the University of California, Los Angeles.
A masked pro-Israeli group assaulted a pro-Palestinian student camp, before officers were called to the campus.
Governor Gavin Newsom's spokesperson said the "limited and delayed" police intervention was "unacceptable".
Hundreds of police swarmed the campus early on Wednesday morning after more than two hours of fighting.
State officials and university leaders have said they immediately deployed security personnel to the tent camp on Dickson Plaza when clashes erupted just before midnight on Tuesday.
But several people on site said law enforcement did not act quickly enough.
"Law enforcement simply stood at the edge of the lawn and refused to budge as we screamed for their help," UC Divest at LA, a group involved in the encampment, said in a statement.
The OceanNewsUK has contacted UCLA and LAPD for a response.
The university declared the pro-Palestinian encampment, in the shadow of its Royce Hall, an illegal gathering on Tuesday.
Footage online shows that, as midnight approached on Tuesday, a large pro-Israeli group donning black outfits and white masks arrived on campus and attempted to dismantle barriers.
Campers, some wearing goggles and helmets, and others carrying placards and umbrellas, rallied to defend their makeshift space.
Dylan Winward, a reporter with the Daily Bruin student newspaper, said the counter-demonstrators had thrown objects including "fireworks, a scooter, water bottles and tear gas".
The Bruin also said on social media that four of its reporters had been assaulted and sprayed with an irritant early on Wednesday morning by attackers who recorded the incident on their mobile phones.
"Tonight they escalated to a whole new level, they started inciting violence," one pro-Palestinian student activist told the OceanNewsUK.
Protesters started leaving the site roughly two hours after the attack began and police had established control as day broke on Wednesday morning. It is unclear whether police made any arrests.
Governor Newsom condemned the violence in a post on X, formerly Twitter, separate to his office's statement.
"The law is clear," he said. "The right to free speech does not extend to inciting violence, vandalism or lawlessness."
He said those responsible "must be held accountable... including through criminal prosecution, suspension, or expulsion".
Citing law enforcement sources, the Los Angeles Times reports there were only a few UCLA police officers on hand and they retreated because they were outnumbered by the crowd.
According to the newspaper, reinforcements were called from California Highway Patrol and Los Angeles and it took three hours to bring the situation under control.
The overnight clash at one of America's top public colleges took place only hours after police in New York City raided and cleared a Columbia University building taken over by students.
Protests at Columbia against the war in Gaza have inspired similar actions at universities - small and large, public and private - in more than two dozen states, with activists demanding that institutions cut financial ties with Israel and companies profiting from the war.
On Wednesday, state troopers arrested 17 anti-war protesters at the University of Texas at Dallas, said the OceanNewsUK's Tom Bateman on campus, while the NYPD arrested at least 15 people at Fordham University in the Bronx.
UCLA cancelled classes on Wednesday, as it sought to ease tensions on the central quad of its Westwood campus.
Mary Osako, a UCLA vice-chancellor, said police and other first responders were called to the scene of its encampment over "horrific acts of violence" early on Wednesday morning.
"We are sickened by this senseless violence and it must end," she said.
Los Angeles Mayor Karen Bass slammed the clashes as "absolutely abhorrent and inexcusable". Speaking later on Wednesday, she called for an investigation into the violence.
"Those involved in launching fireworks at other people, spraying chemicals and physically assaulting others will be found, arrested and prosecuted, as well as anyone involved in any form of violence or lawlessness," she said.
By morning, a tight security cordon was in place as a handful of protesters fortified their encampment.
It remains unclear how many of the people involved in the night-time chaos, particularly on the pro-Israeli side, are students at the university.
The Los Angeles chapter of the Council on American-Islamic Relations blamed the violence on a "mob of pro-Israel extremists".
Meanwhile, the Jewish Federation Los Angeles sought to distance itself from the violence, but blamed the university's chancellor for allowing "an environment to be created over many months that has made students feel unsafe".
"The abhorrent actions of a few counterprotesters last night do not represent the Jewish community or our values," the group wrote. "We believe in peaceful, civic discourse."
Earlier on Wednesday, New York City Mayor Eric Adams said several out of some 300 arrests at two New York campuses had been "outside agitators".
Pressure has been mounting on college leaders to rein in pro-Palestinian protests as they spread across the country.
But University of California leaders had sought to pursue a more light-touch approach to the demonstrations that colleagues across the country.
College guidance to managing protests changed in 2011, after heavy handed policing during a demonstration on campus sparked outrage. Guidelines stated that the college should allow protests as long as they are peaceful, with police action used as a last resort.
