Police and protesters clashed on the campus of the University of Texas at Austin on Monday afternoon after authorities issued a dispersal order.

The UT Austin Police Department asked protesters to leave the South Mall area at about 1 p.m. local time.

Protesters could be heard chanting, "There is no riot here, why are you in riot gear?" Soon after, police moved in to clear the area by force.

The university said in a statement, "After protesters ignored repeated directives from both the administration and law enforcement officers to comply with Institutional Rules and remove tents assembled on the University’s South Lawn, then physically engaged with and verbally assaulted Dean of Students staff who attempted to confiscate them, UT and partner law enforcement agencies dismantled an encampment and arrested several protesters."

It continued, "Baseball size rocks were found strategically placed within the encampment. The majority of protesters are believed to be unaffiliated with the university."

More than 50 people were arrested at a pro-Palestinian protest on the campus last week, however, charges were later dropped.

Protesters camped out at Columbia University are defying the school's order to pack up and leave by 2 p.m.

Sueda Polat, a representative from the protesters' negotiating team, told reporters that the university did not engage in good-faith negotiations and failed to meet their demands to divest from Israel.

"It is against the will of the students to disperse," she said. "We do not abide by university pressures. We act on the will of the students."

Police were outside of the campus as the deadline approached but they did not immediately enter after it passed.

"Students are aware of the risk of law enforcement. ... They know how to come together in that risk," Polat said.

Cal Poly Humboldt said it will close off campus to non-school members through May 10 as protesters have occupied two buildings.

Campus leaders also said it will now offer escorts off campus to anyone who feels their safety is threatened.

The school urged the protesters who have been occupying Siemens Hall and Nelson Hall East since last week to leave immediately.

"Leaving voluntarily will be considered as a possible mitigating factor in University conduct processes and may reduce the severity of sanctions imposed. This does not, however, eliminate responsibility for any potential conduct or criminal charges."

-ABC News' Bonnie McLean

The University of Georgia-Athens said protesters who set up an encampment on campus "crossed a line" Monday morning and several were arrested.

Approximately "25 protesters began erecting tents and a barricade, blocking sidewalks and building entrances and using amplified sound," school spokesman Greg Trevor said in a statement.

The protesters met with university police and student affairs members to discuss the violation and were given multiple warnings to remove the barriers, but they refused, according to Trevor.

"At 8:30 a.m., UGA Police were left with no choice but to arrest those who refused to comply," he said.

The school did not specify how many people were arrested.

"While we must provide ample opportunity for protected expressive activities, we also have the right and duty to regulate the time, place and manner in which they occur," Trevor said.

-ABC News' Ahmad Hemingway

New York City Mayor Eric Adams urged protesters at Columbia University to "walk away" after dozens of demonstrators stormed the campus' Hamilton Hall in what he called a "violent spectacle that serves no purpose."

Adams said the peaceful demonstrations were being co-opted by "professional outside agitators" seeking to "create discord and divisiveness."

"That is why I'm urging every student, every protester to walk away from this situation now. Continue your advocacy through other means," Adams said at a press briefing Tuesday evening. "We will always protect the right to protest, but we must balance that right with the right to keep students in school and our city safe."

"We cannot wait till this situation becomes even more serious. This must end now," he added.

Chief Edward Caban reiterated that protesters who are not Columbia students are working to escalate the situation and said the New York City Police Department is ready to assist the university as needed.

"We have seen the tactics changing in a way that's endangering public safety," he said.

The NYPD showed footage of what Deputy Commissioner for Intel Rebecca Weiner said showed outside actors making barriers inside Hamilton Hall and "escalating" tactics such as scaling buildings and breaking windows. Cameras in the building have also been destroyed, Weiner said.

Individuals who occupied Hamilton Hall could face charges including burglary in the third degree, trespass and criminal mischief, police said.

A Columbia University spokesperson said Tuesday evening that dozens of protesters were in Hamilton Hall.