Of the approximately 280 arrests at Columbia University and City College, 170 are summonses, while the remaining people will receive desk appearance tickets or will work through the court system, according to Manhattan District Attorney Alvin Bragg.

Each case would be evaluated individually, including a review of body camera footage and other evidence, Bragg said. But, he did not reveal how many of those arrested were affiliated with the colleges and how many were outside agitators.

-ABC News' Aaron Katersky

Columbia University announced final exams will be held remotely amid a tense campus climate, according to a letter sent out by the university's provost.

"In order to address the concerns of our members in an evolving campus environment, all academic activities for schools on the Morningside Heights campus will be fully remote for the remainder of the semester (with carve-outs noted below). Any remaining class meetings, review sessions, or office hours should be held fully remotely, and all final exams and other final assessments should be fully remote," Columbia said in a statement.

All final exams scheduled for Friday will be automatically rescheduled for May 10.

A total of 34 people were arrested while emptying a pro-Palestinian encampment at University of Wisconsin-Madison Wednesday, the university said.

The majority of those arrested have been released with no citation issued, but four people have been booked, according to the university. The charges they are facing include attempted disarming a police officer, resisting arrest, attempted escape and battery to a police officer.

Four police officers were injured at the University of Wisconsin-Madison where police were dispersing an encampment of protesters on the Library Mall.

Three of the four officers sustained injuries "directly related to the physical resistance," according to the university. A state trooper sustained injuries when a protester allegedly "struck their head with a skateboard."

In a letter authorizing the NYPD to enter the Columbia University campus and break up the protest, the school detailed the backstory on its recent talks with those in the encampments and the takeover Tuesday night of Hamilton Hall.

According to the letter, from Columbia President Minouche Shafik, an individual "hid in the building" at Hamilton Hall until it was closed and let others in. The group's purpose was "occupying the building," the letter read.

Two security guards were inside the building at the time, and the university said in the letter to the NYPD they were able to "secure their release."

"We believe that while the group who broke into the building includes students, it is led by individuals who are not affiliated with the University," the letter read. "The individuals who have occupied Hamilton Hall have vandalized University property and are trespassing."
Addressing the encampment on the school's Morningside campus, the university told police discussions had been carried out with group representatives, but on Sunday, they "reached an impasse."

At that time, the university says it told the group they did not have permission to "occupy spaces on campus" and were "in violation" of school rules and policies.
On Monday morning, the protesters were told they would be suspended if they didn't disperse by Monday at 2 p.m. ET.

The university said in its Tuesday night NYPD letter that those in the encampment were "suspended" and "not authorized to be on University property and are trespassing."

The university said it believed the actions of those in the protest were escalating. "These activities have become a magnet for protesters outside our gates which creates significant risk to our campus and disrupts the ability of the University to continue normal operations," the letter read.

Columbia's president concluded the letter by asking the NYPD to "help to clear all individuals from Hamilton Hall and all campus encampments."

She further asked police to have a campus presence through May 17 -- graduation is May 15 -- "to maintain order and ensure encampments are not reestablished."

Police moved onto the Columbia University campus a little before 9 p.m. ET and began making arrests.

The NYPD also used a vehicle with an extendable roof ramp to help officers breach Hamilton Hall from an upper floor. From there, the police cleared the building.

The campus encampment and hall were cleared before 11:30 p.m.

-ABC News' Jolie Lash, Aaron Katersky and Joshua Hoyos