New York City Mayor Eric Adams and New York Police Department officials told reporters that protesters at Columbia University were being influenced by outside individuals, part of a movement "globally" to "radicalize young people"

"Students have a right to protest and free speech is the cornerstone of our society. But as our major concern we knew and we saw that there were those who were never concerned about free speech. They were concerned about chaos. It was about external actors hijacking peaceful protests influence students to escalate," Adams said.

"You don't have to be a majority to influence and co-opt an operation," Adams said.

About 300 people were arrested at Columbia University and City College Tuesday night, New York Mayor Eric Adams said Wednesday.

"We are processing the arrests to distinguish between who were actually students and who were not supposed to be on the grounds," Adams said.

"It was led by individuals who are not affiliated with the university. The school needed the NYPD assistance to clear Hamilton Hall at the encampments outside of dual operations on the grounds that took place successfully," Adams said.

Officials said those arrested could be charged with trespassing, criminal mischef and burglary.

Campus police officers at the University of Arizona in Tucson shot "chemical irritant" munitions at a gathering of protesters early Wednesday, the department said.

The university's president, Robert C. Robbins, had asked the campus police and school officials to "immediately enforce campus use policies and all corresponding laws," according to a statement from his office.

The Tucson Police Department and other law enforcement agencies also responded to campus, the university said.

Campus officers closed several blocks of Park Avenue as they responded to the "unlawful assembly," the department said.

Video appeared to show police handcuffing individuals on the ground and protesters forming a human chain facing officers.

"Police deploying chemical irritant munitions," the department said amid a series of updates on social media. "Follow orders of police and disperse immediately. Avoid the area of University Blvd & Park Ave."

-ABC News' Amanda Morris and Kevin Shalvey

As groups of counter-protesters clashed with Pro-Palestinian demonstrators on the UCLA campus early Wednesday, a university official said staff were “sickened” by the violence.

“Horrific acts of violence occurred at the encampment tonight and we immediately called law enforcement for mutual aid support,” Mary Osaka, a vice chancellor, said in a statement.

Osaka aded that the fire department and medical responders were near the scene.

"We are sickened by this senseless violence and it must end,” she said.

-ABC News’ Bonnie Mclean and Kevin Shalvey

At least 25 people were arrested at CUNY's City College of New York campus as police confronted protesters early Wednesday, the university said in a statement.

University officials said they asked the New York Police Department for assistance in clearing protesters, including a "large crowd" of people who had marched from Columbia University to City College.

The school described a "series of violent indents" that it said put public safety at risk over the last six days.

"This includes a fire Sunday night at the Marshak Science Building caused by use of a flare gun that brought FDNY to campus, clashes with public safety, an attempted break-in at Shepard Hall tonight, and a break-in at the Administration Building tonight that included the vandalizing of offices and smashing glass doors," the university said in a press release early Wednesday.

Police entered the campus just before midnight and began making arrests, the university said.

"Students have a right to demonstrate peacefully and exercise their First Amendment rights," the university said. "Tonight's actions were taken in response to specific and repeated acts of violence and vandalism, not in response to peaceful protest"

-ABC News' Jessica Gorman and Kevin Shalvey