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.

Columbia University has distributed a letter to members of the encampment on campus telling them to gather their belongings and leave the area by 2 p.m., saying if they identify themselves and sign a form "to abide by all University policies through June 30, 2025, or the date of the conferral of your degree, whichever is earlier, you will be eligible to complete the semester in good standing."

The school said it has "already identified many students in the encampment" and "if you do not identify yourself upon leaving and sign the form now, you will not be eligible to sign and complete the semester in good standing." The school warned it could take action up to suspension or expulsion if they do not leave the encampment.

The school reiterated that negotiations with protesters had broken down and said the protests are a "disruption" to those taking final exams and preparing for graduation.

"As you are probably aware, the dialogue between the University and student leaders of the encampment is, regrettably, at an impasse," the letter states. "The current unauthorized encampment and disruption on Columbia University’s campus is creating an unwelcoming environment for members of our community. External actors have also contributed to this environment, especially around our gates, causing safety concerns – including for our neighbors."