A pro-Palestinian encampment on the campus of the University of Southern California was being cleared Sunday morning as campus police warned protesters to leave or be arrested.

The announcement came as the USC Department of Public Safety closed the campus "as a result of significant activity at the center of campus."

"If you are in the center of campus, please leave. People who don’t leave will be arrested. We will issue another alert when it is clear to return," the DPS said on X.

The campus police said officers from the Los Angeles Police Department are assisting in "clearing the center" of the University Park Campus.

Sunday's action came after USC President Carol Folt sent an email to the school's community, saying "steps would be taken to ensure a quiet and safe environment for students to complete their finals."

“[L]et me be absolutely clear: free speech and assembly do not include the right to obstruct equal access to campus, damage property, or foment harassment, violence, and threats,” Folt said. “Nor is anyone entitled to obstruct the normal functions of our university, including commencement."

-ABC News' Cory Peeler

Authorities arrested 25 protesters at the University of Virginia for trespassing on Saturday, according to the university's communications office.

The school said it was still awaiting confirmation on how many of those arrested were affiliated with UVA.

Approximately 50 people were arrested, including some students, at The Art Institute of Chicago on Saturday, according to a spokesperson from the museum.

"Today, a group of individuals, including some SAIC students, began a protest in the museum’s North Garden, and as it progressed, protesters surrounded and shoved a security officer and stole their keys to the museum, blocked emergency exits, and barricaded gates," the statement read.

Protesters were offered an alternative location to continue the protest on campus, but they did not accept that offer, according to the spokesperson.

"During multiple rounds of negotiations, SAIC student protesters were promised amnesty from academic sanction and trespassing charges if they agreed to relocate. The School also agreed to meet with a student group to discuss their demands. After approximately five hours, an agreement could not be reached."

Chicago Police Department assisted with ending the protests and arresting individuals, the museum spokesperson said.

The president of the University of Virginia, Jim Ryan, released a statement Saturday on the removal of protesters from the encampment on campus.

Ryan said that up until Friday, the demonstrations on campus had remained peaceful and "complied with requests to adhere to University policies including a long-standing prohibition on erecting tents absent a permit."

However, Ryan said protesters were given a "final warning" on Saturday morning that "was ignored" and the university’s police department officers "were met with physical confrontation and attempted assault."

Virginia State Police were called to clear the encampment after it was deemed an "unlawful" assembly, according to the president.

"I recognize and respect that some will disagree with our decisions,” Ryan said in the statement. “This entire episode was upsetting, frightening and sad."

New York City Mayor Eric Adams on Sunday defended the police crackdown on college campus protests that have broken out in America's largest city.

"When those protests reach the point of violence, we have to ensure that we use a minimum amount of force to terminate what is perceived to be a threat," " Adams told ABC News "This Week" co-anchor Jonathan Karl.

Adams added that the police intervention resulted from days of communication between the police and school officials.

"We knew we had to get permission unless there's imminent threat to life, or severe threat to property," he said, adding, "We were not going to overstep our legal authority."

When pressed by Karl about criticism, including from some other Democrats, that the response to protesters was disproportionate given that they were largely nonviolent, Adams said, "One has the right to have his or her opinion, and I respect that. ... And I have an obligation and responsibility to ensure the city is safe."

-ABC News' Kristina Abovyan