Tensions at the University of California, Irvine campus escalated Wednesday as a group of several hundred pro-Palestinian protesters entered a lecture hall and surrounded the building, according to school officials.
The Irvine Police Department and the Orange County Sheriff's Department were called to the scene after the university called for mutual aid from local law enforcement agencies, UC Irvine said in an emergency update.
Authorities were seen putting protesters in zip-ties and escorting them away from the main protest area.
MORE: Organizing massive campus protests required logistical savvy. Here's how students pulled it off.The school initially said Thursday that 50 people were arrested during the incident, but later corrected that number to 47 individuals, mostly for failure to disperse, though some were arrested for trespassing.
Among the total number of arrests, 19 individuals were not affiliated with the university, two were school employees and 26 were students.
"I was prepared to allow a peaceful encampment to exist on the campus without resorting to police intervention, even though the encampment violated our policies and the existence of the encampment was a matter of great distress to other members of our community," Chancellor Howard Gillman said in a letter to the community Thursday.
"And so after weeks when the encampers assured our community that they were committed to maintaining a peaceful and nondisruptive encampment, it was terrible to see that they would dramatically alter the situation in a way that was a direct assault on the rights of other students and the university mission," he continued.
Police took down barricades from the encampment and people were asked to leave the building.
Protesters entered the Physical Sciences Lecture Hall on the UC Irvine campus at approximately 2:30 p.m. local time, according to the university.
Classes for the remainder of the day were canceled and school officials urged anyone in the immediate area to evacuate until further notice.
"Anyone currently in buildings in the vicinity of the protest are advised to exit buildings & leave area at this time," UC Irvine wrote in an update on X. "Please disregard all previous orders to shelter in place. If able, please leave immediately & continue to avoid the protest area until further notice."
By Wednesday night, police had broken up the campus encampment.
UCI said classes on Thursday would be remote.
"UC Irvine will move to remote instruction on Thursday, May 16. Unless specifically noted, all employees should work remotely. Resident students may still access dining facilities. Protest activity continues. Please avoid area until further notice," read a post on the school's X page Wednesday night.
"I’m sorry this campus I love so much had to experience this terrible and avoidable situation," Gillman wrote Thursday. "I remain steadfast in my commitment to protecting the rights of all members of our community to express whatever viewpoints they believe are essential for others to hear and engage."
Pro-Palestinian protesters have been present on the UC Irvine campus since establishing an encampment on April 29, according to the university.
MORE: College encampments protesting Israeli military operations in Gaza grow nationwide: What students are sayingWednesday's unrest comes amid weeks of protests breaking out at universities across the country, calling for institutions to divest from companies that financially support Israel.
On Tuesday, UC Chief Investment Officer Jagdeep Singh Bachher announced that investments from companies that students are targeting in their call for divestment represent $32 billion, which is nearly one-fifth, of the UC system's overall assets.
Last month, the University of California president said the institutions would not boycott or divest from Israel.
ABC News' Marilyn Heck and Vanessa Navarrete contributed to this report.