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.

Over 300 Harvard University professors have signed a letter to the university urging "constructive dialogue" with the peaceful protesters on campus.

"We are concerned that the university has yet to meet with the students to hear their concerns. Instead, the administration has issued escalating threats of punitive disciplinary action, the severity of which the university has not seen in decades," professors wrote.

"We urge the administration to meet and engage in meaningful dialogue with peacefully protesting students," the letter said.

The letter, sent to interim President Alan Garber and interim Provost John F. Manning Tuesday, came after Harvard warned protesters to empty their encampment. The professors are urging Harvard's administration to follow the lead of Brown University and Northwestern University, where encampments ended after school leadership agreed to take steps toward divestment.

"I think so many of us signed this letter because, as faculty, we have a duty of care towards our students. The harshness and scale of the proposed punishment is unprecedented and frankly alarming; these are activities that should be met with dialogue, not punishment," Teju Cole, a Gore Vidal professor of the practice of creative writing at Harvard, said in a statement.

"We are calling on the administration to be fair-minded and set these protests in the context of numerous other protests that have happened here in the past, in response to which the university did the right thing," Cole said.