The University of Southern California's University Park campus has reopened Sunday after a pro-Palestinian tent encampment was cleared out and dismantled, the university said.

All students, faculty and staff must present valid identification, USC said.

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

A pro-Palestinian tent encampment on the University of Southern California campus was cleared out and dismantled Sunday morning without any arrests being made, university officials said.

Joel Curran, a spokesperson for USC, said in a statement that the encampment, established by protesters 12 days ago, was "peacefully" taken down.

“Earlier today, the University of Southern California Department of Public Safety (DPS) successfully removed the illegal encampment rebuilt on the university’s campus. It was necessary to request the Los Angeles Police Department to respond to provide security as this was carried out peacefully," Curran said. "No arrests have been reported. We want to thank LAPD for assisting DPS in clearing the encampment and restoring normalcy for students and community as quickly and safely as possible. We will share more information with our community later today.”

-ABC News' Tristan Maglunog

The University of Southern California said the encampment at University Park Campus has been cleared and the campus remains closed.

Linda G. Mills, the president of NYU, posted a statement Friday evening explaining why the school called in the NYPD to break up an encampment on the Greene St. Walkway earlier in the day.

Mills said 14 people who refused orders to leave the area were arrested and the incident was non-violent.

The president said that the police were called in for numerous reasons, including noise complaints from nearby residents and businesses, safety concerns over the crowds of supporters and counter-protesters and escalating threats.

"The encampment had become increasingly untenable for the NYU community and the neighborhood we inhabit," she said.

Mills said three senior administrators spoke with the protesters over the weekend to come to an agreement over shutting down the encampment.

The president said things escalated on Wednesday when a group of people from a May Day march came to the walkway and got into altercations.

The May Day incident and other issues, including threats leveled at NYU administrators, led the school to call the NYPD, according to Mills.

"The university’s senior leadership and I were compelled to conclude that we could not tolerate the risk of violence any longer and that we could not responsibly or in good conscience wait until something drastically worse were to happen in order to act. We needed to bring this to a close," she said.