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

The New York Police Department made at least 100 arrests overnight, with most at Columbia University. Arrests were also made at City College of New York, officials said.

Many of those taken into custody are still being processed at police headquarters.

-ABC News’ Aaron Katersky

Clashes between opposing groups of protesters at the University of California Los Angeles included "multiple acts of violence," prompting university officials to ask police to enter the campus, the Los Angeles Police Department said.

Officers responded to assist campus police "to restore order and maintain public safety," the LAPD said.

State and local politicians said they were monitoring the situation, with Los Angeles Mayor Karen Bass calling the violence "absolutely abhorrent and inexcusable."

Gov. Gavin Newsom said his office had been in contact with law enforcement leadership.

-ABC News' Bonnie Mclean, Amanda Morris and Kevin Shalvey

Northwestern University announced it has reached a deal with pro-Palestinian protesters, ending an encampment of students and faculty, but allowing peaceful demonstrations to continue through June 1.

The university said it would "answer questions from any internal stakeholder about holdings, held currently or within the last quarter, to the best of its knowledge and to the extent legally possible" -- meeting a key call from divestment protesters and students around the country who are seeking more transparency over universities' investments.

Northwestern will also reestablish an Advisory Committee on Investment Responsibility in the fall, which will include representatives from students, faculty and staff.

The university also pledged more inclusivity, funding two Palestinian faculty members and the full cost of attendance for five Palestinian undergraduate students annually, as well as a commitment to raising funds to sustain the program beyond this commitment.

Under the agreement, Northwestern says tents will be removed immediately but one aid tent will be allowed to remain. Protesters will need to suspend the use of "non-approved" amplified sound." Protesters who refuse to follow the agreement will be suspended and non-affiliated individuals must leave campus.