CNN — More than 100 people were arrested by New York Police Department officers on a preliminary charge of criminal trespass, according to a law enforcement official, as police entered Columbia University on Thursday to disperse a pro-Palestinian protest that began a day earlier as the university’s president testified before a House committee about the school’s response to antisemitism.

The individuals were detained with no resistance, and the university is named as the complainant since the incident occurred on its property, the official told CNN.

Columbia President Nemat “Minouche” Shafik was in Washington, DC, testifying to the House education committee, as the protesters – including students, faculty and others – gathered in upper Manhattan early Wednesday morning, setting up tents and signs.

Later that afternoon, competing rallies of pro-Israel and pro-Palestinian groups grew.

Several people waving Palestinian flags had verbal confrontations with police officers, who had begun boxing the protesters in with barricades, CNN affiliate WCBS reported. In video from WCBS, pro-Palestinian protesters could be seen clashing with police and some had lit small fires. One woman could be seen being led away in handcuffs.

Four people were arrested overnight during protests at Columbia, the NYPD said. Police did not specify what charges were filed and gave no additional details about the arrests.

Hamas fighters launched a devastating attack on Israel on October 7, killing 1,200 people and taking 250 others hostage. Since Israel declared war on Hamas, more than 33,000 Palestinians have been killed and over 76,000 have been injured in the besieged enclave since the beginning of Israel’s war in Gaza, according to the health ministry there.

Students and faculty set up a tent encampment on campus lawns Wednesday. One of the organizing groups, including “Uptown4Palestine,” said the protest was in part aimed at raising awareness about “the ongoing genocide and displacement of Palestinians.”

During Wednesday’s protests, Columbia closed the gates to campus, only allowing individuals with Columbia IDs to enter. Many of the pro-Palestinian protesters affiliated with Columbia camped on the campus overnight.

Shafik wrote a letter to the NYPD on Thursday asking for the department’s help to “remove these individuals.”

“The actions of these individuals are in violation of University rules and policies,” the president wrote. “The University provided multiple notices and warnings and informed the encampment participants that they must disperse or face immediate discipline.”

The president told students she authorized the NYPD to break up the encampment, according to an email obtained by CNN. Shafik wrote she authorized the move “out of an abundance of concern for the safety of Columbia’s campus.”

“I took this extraordinary step because these are extraordinary circumstances,” Shafik wrote. “The individuals who established the encampment violated a long list of rules and policies.”

NYPD officers used bullhorns to tell protesters they would be arrested unless they dispersed immediately. Large crowds of Columbia students on the perimeter chanted, “Shame on you” and, “The students united will never be defeated.”

Shortly after 2 p.m., a group of at least 200 protesters moved to an area about two blocks away from the school campus near the NYPD staging site and police said they would soon disperse the crowd, CNN witnessed. Officers in helmets, carrying batons, were seen lining up in the street surrounding the group.

In the past, the office of Manhattan District Attorney Alvin Bragg has declined to prosecute or deferred prosecution cases where large numbers of people were arrested as part of civil disobedience.

Video footage online appears to show NYPD officers clashing with protesters outside the university on Thursday morning. The Metropolitan Transportation Authority Thursday posted a message on social media warning riders buses in the area are delayed because of a protest at the university.

Rep. Ilhan Omar’s daughter among those arrested, police official says

Isra Hirsi, the daughter of Rep. Ilhan Omar, was among those arrested Thursday, a police official told CNN. The official said Hirsi is being processed and will likely receive a summons for a criminal trespass charge then be released from custody.

Hirsi, an organizer with Columbia Students for Justice in Palestine, said earlier Thursday she and two other students at Barnard College – located across the street from Columbia University – were suspended for participating in pro-Palestinian protests.

In a statement on X, Hirsi said she has “never been reprimanded or received any disciplinary warnings” in her three years at the college.

“I just received notice that I am 1 of 3 students suspended for standing in solidarity with Palestinians facing a genocide,” Hirsi said.

Barnard is an official college of Columbia University, but also an independently incorporated educational institution.

When asked about the suspensions, a Barnard College spokesperson said the college “does not provide information about confidential student conduct proceedings,” and referred CNN to a message sent to the college community.

Current students and Columbia alumni attended the demonstration. Among them was Nas Issa, who graduated from Columbia in 2020. Issa is a member of the Palestinian Youth Movement and is currently assisting in mobilizing support to help the students arrested.

“We were part of the pickets that are circling the lawns, to protect them and to show them that their community is with them,” Issa told CNN.

Ry, who withheld his last name to protect his identity, told CNN he had been camping at the campus until arrests were being made.

“I want people to remember that we might be detached from the Palestinian people culturally and geographically,” said Ry, who is a senior at Columbia studying history and a member of Jewish Voice for Peace.

“But we as students are using our privilege to stand for people who have been oppressed for far too long and we hope other universities take the call and do the same,” he continued.

University under fire for hiring professor who made controversial remarks

Shafik and the university have been criticized for how their officials have handled antisemitic, Islamophobic and anti-Arab harassment incidents on campus.

During the the House Committee on Education and the Workforce hearing, Shafik said the core of the university’s mission is to “ensure that all members of our community may engage in our cherished traditions of free expression and open debate,” quoting from the school’s rules of university conduct.

“We believe that Columbia’s role is not to shield individuals from positions that they find unwelcome, but instead to create an environment where different viewpoints can be tested and challenged,” Shafik added. However, she acknowledged that freedom of speech has been used to justify chants and language that has made students feel unsafe.

Last fall, a Columbia student who was hanging posters on campus in support of Israel was assaulted. Days later, a mobile “doxxing” billboard drove outside the entrance of Columbia displaying the names and faces of students who a conservative nonprofit said were linked to a statement blaming Israel for the Hamas terror attack.

University leaders had issued a statement condemning “disturbing antisemitic and Islamophobic acts, including intimidation and outright violence.”

The university has also faced criticism for hiring a professor who allegedly expressed support for Hamas on social media following the October 7 terror attack on Israel. That professor has been fired, Shafik said Wednesday.

Columbia did not immediately respond to a request for comment on when the professor’s termination takes effect.