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

Columbia University has distributed a letter to members of the encampment on campus telling them to gather their belongings and leave the area by 2 p.m., saying if they identify themselves and sign a form "to abide by all University policies through June 30, 2025, or the date of the conferral of your degree, whichever is earlier, you will be eligible to complete the semester in good standing."

The school said it has "already identified many students in the encampment" and "if you do not identify yourself upon leaving and sign the form now, you will not be eligible to sign and complete the semester in good standing." The school warned it could take action up to suspension or expulsion if they do not leave the encampment.

The school reiterated that negotiations with protesters had broken down and said the protests are a "disruption" to those taking final exams and preparing for graduation.

"As you are probably aware, the dialogue between the University and student leaders of the encampment is, regrettably, at an impasse," the letter states. "The current unauthorized encampment and disruption on Columbia University’s campus is creating an unwelcoming environment for members of our community. External actors have also contributed to this environment, especially around our gates, causing safety concerns – including for our neighbors."

Protesters at Columbia University, who sparked many of the protests across the nation earlier this month, are now being asked to voluntarily disperse after the school's president said it was not able to come to an agreement through negotiations.

Since Wednesday, "a small group of academic leaders has been in constructive dialogue with student organizers to find a path that would result in the dismantling of the encampment and adherence to University policies going forward. Regretfully, we were not able to come to an agreement," Columbia President Minouche Shafik said in a statement Monday morning.

One of the top demands of the protesters, for Columbia to divest from Israel, was flatly denied by the university, according to the statement.

The school asked protesters, who number in the hundreds, to voluntarily disperse, but offered no explanation for what would happen if they did not. The school said it did not "want to deprive thousands of students and their families and friends of a graduation celebration." The school's graduation ceremony is set to be held May 15.

"We urge those in the encampment to voluntarily disperse," Shafik wrote. "We are consulting with a broader group in our community to explore alternative internal options to end this crisis as soon as possible. We will continue to update the community with new developments."

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