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

President Joe Biden addressed the nation on Thursday saying that free speech and the rule of law must both be upheld.

"We are not an authoritarian nation where we silence people or squash dissent, the American people are heard. In fact, peaceful protest is the best tradition of how Americans respond to controversial issues," Biden said, speaking from the White House.

But, he condemned the destruction of property, shutting down campuses and forcing the cancelation of classes and graduation, saying it isn't peaceful protest.

"Dissent is essential to democracy, but dissent must never lead to disorder or to denying the rights of others so students can finish the semester and their college education," Biden said.

Biden last commented on college protests on April 22 -- before there was an escalation of suspension and arrests at campuses across the country -- at the time condemning antisemitic actions and those who don't understand the plight of Palestinians in Gaza, a message he reiterated Thursday.

"There is no place for hate speech or violence of any kind whether it's anti-Semitism, islamophobia or discrimination against Arab Americans or Palestinian Americans. It’s simply wrong. There’s no place for racism in America," Biden said.