Columbia University closed its campus to the public on Thursday before a planned protest against the Israeli bombardment of Gaza, and one day after a 24-year-old Israeli student was beaten in front of a library on campus.

The assault of the Columbia student, who was hanging flyers at the time of the attack, was one of several in New York in the last 24 hours that police were treating as possible bias incidents.

It led to the arrest of a 19-year-old woman who was charged with assault, according to the Police Department. Police did not identify the victim. On Thursday, a university spokesperson, Samantha Slater, said the school was restricting access to campus “to help maintain safety and a sense of community through planned demonstration activities.”

Pro-Israel demonstrators counterprotest a demonstration against the Israeli bombardment of Gaza at Columbia University in New York, on Thursday, Oct. 12, 2023. Tensions have risen around the city as supporters of each side stage protests and police investigate possible hate crimes. Bing Guan/The New York Times

New York City has been wracked by grief, shaken by protests and living on edge in the days since a Hamas attack killed more than 1,200 Israelis and an Israeli bombing campaign in the Gaza Strip killed more than 1,100 people and flattened large areas of the densely populated and impoverished region.

Some events, like a rally in Times Square last weekend where protesters cheered rocket attacks on Israel, have raised tensions between the Jewish community and a pro-Palestinian leftist movement that has grown in influence in recent years. Others, like a candlelit gathering in Washington Square Park where mourners prayed for the dead in Israel and Gaza and denounced the war, have been more muted.

“Every single life lost — every Israeli murdered by Hamas, every Palestinian killed in Gaza — is a human spark that is extinguished,” Brad Lander, the city comptroller, told the assembled mourners in Washington Square on Wednesday night. “We mourn those human beings, and we mourn the loss of that human spark.”

Protests were organized at several campuses of the City University of New York on Thursday, including in Brooklyn and Manhattan and on Staten Island.

More than 100 demonstrators rallied outside Brooklyn College to protest the Israeli bombardment of Gaza, with a smaller group of pro-Israel demonstrators gathered nearby.

“We have to be the voice of Palestine because they have no voice right now,” said Syed Ahmad, 22, a business student whose family is from Pakistan. “We have every right to stand up for what’s right.”

Nearby, David Brodsky, 52, a professor of Judaic studies at Brooklyn College, stood with the pro-Israel demonstrators. “This is a time for moral clarity,” he said.

“We say, ‘We feel your pain,’” Brodsky said, referring to the other group of protesters. “We’re not denying their pain, but they must be able to feel ours too, and we must be able to come together.”

The protests were largely peaceful, but tensions flared.

Several pedestrians passing the demonstrations in Midwood, a neighborhood with many Jewish residents, jeered pro-Palestine demonstrators, calling them “terrorists” and “idiots.” In response, protesters shouted back, “Murderers!”

“You are sick people, animals, you don’t deserve to be here!” one woman standing with the pro-Israel protesters yelled at those gathered in support of Gaza.

The pro-Palestine group chanted “Jews, yes! Zionism, no!”, but some expressed darker sentiments. One man held a sign that said “Decolonize Palestine by any means necessary.”

In an email to the Columbia University community, Dennis A. Mitchell, the institution’s interim provost, said Columbia was bracing for dueling protests staged by two groups, Students for Justice in Palestine and Students Supporting Israel.

He said one or both groups had made “substantial efforts” to draw protesters to campus who were not affiliated with the school “in a manner that risks creating an unsafe environment for our community.”

“Freedom of speech is a fundamental value we hold dear, one that fosters intellectual growth, critical thinking, and the exploration of different perspectives,” Mitchell wrote. “However, it is crucial to emphasize that with this freedom comes the responsibility to ensure that our campus remains safe.”

Another protest against Israel’s bombardment of Gaza was scheduled for Friday afternoon. The group organizing it, Within Our Lifetime, said the demonstration would be held near Times Square as part of an “International Day of Action for Palestine, in defense of liberation, justice and freedom for the Palestinian people.”

The protests have heightened anxieties in the city, which were already high after the Times Square rally. Khaled Meshal, a former Hamas leader, called for protests across the Arab and Muslim world on Friday in a video message sent to the Reuters news agency.

But law enforcement officials said Thursday that there were no credible threats to New York. They said plans were being made to deploy a large number of uniformed officers if necessary. And in a statement sent to Jewish leaders, the Anti-Defamation League said it was not aware of any credible threats to Jewish communities in the United States.

In addition to the assault at Columbia, the Police Department’s hate crime task force said it was investigating two incidents that occurred in Brooklyn on Wednesday night.

One incident occurred near the Navy Yard, near South Williamsburg, at around 8 p.m.

Four men — two Jewish and two of Middle Eastern descent — were waving a Palestinian flag and holding a sign that said “End the War” when a man wearing “traditional Jewish attire” rode up to them on a two-wheeled vehicle, a law enforcement official said. He then grabbed the Palestinian flag from the men and beat one of them with it, the official said.

Later that night, a group of men waving an Israeli flag shouted anti-Palestinian statements at an 18-year-old, a 19-year-old and a 21-year-old as they walked down the street in Bay Ridge at 11:30 p.m.

Shortly afterward, three cars parked in front of the same group of young people, blocking their path, and then a group of men emerged from the cars and attacked the 18-year-old, punching and kicking him repeatedly. Police said that they were looking for suspects in both incidents Thursday and that no arrests had been made.

The New York Times News Service