The activists, whose demands include divestment from Israel and an end to academic ties with the country, also included 23 undergraduate and graduate students, six students from affiliated schools and two Columbia employees. Earlier Thursday, New York City Mayor Eric Adams said outsiders accounted for a little less than a third of the 112 people arrested in a crackdown that occurred at Columbia on Tuesday evening.

The number of outsiders was higher during a separate police action that occurred further uptown at the City College of New York, Adams said. There, 60% of the 170 protesters arrested were unaffiliated with the school.

NYPD Makes About 300 Arrests in Crackdown at Columbia, CUNY

Most of those arrested at the two schools were released with summonses, according to the police. Charges include burglary, reckless endangerment, criminal mischief, conspiracy, and criminal trespass, among others. Police Commissioner Edward Caban reiterated the department’s view that the escalation of the protests — from gatherings to encampments to the building takeover at Columbia — reflected the involvement of outsiders.

“We saw a shift in tactics, and the safety of all students, school faculty, staff, and the public became a real concern,” Caban said in the statement Thursday.

One of the police officers involved in the Columbia raid fired his gun inside the hall, the Associated Press reported Thursday, citing a spokesman for the Manhattan District Attorney’s office. No one was injured and no students were in the vicinity, and the incident is under review, the AP said.

Protests condemning the Israel-Hamas war have intensified at campuses across the US in recent weeks. The showdowns have sparked recriminations and support from politicians, faculty and billionaire donors.

At Columbia, the situation escalated to new heights early Tuesday when protesters occupied Hamilton, an academic building, blocking doors and stairwells with furniture, and chaining entries closed.

Columbia has said the student occupiers face expulsion and the disciplinary process is underway. The university’s president, Minouche Shafik, has asked the police to maintain a presence on campus through at least mid-May, after graduation.