It has been more than 50 years since the United States saw college students launch anti-Vietnam War protests across the nation.

Now, students have again become the front line in a new conflict — this time as Israel fights Hamas in Gaza.

It was Columbia University in New York City that sparked the anti-war protests in 1968 when students seized five buildings, including Hamilton Hall. On April 18, pro-Palestinian demonstrators occupied the hall, just as their predecessors had done 56 years ago to protest against the Vietnam War.

Columbia has again become the epicenter of demonstrations that have spread nationwide to 46 other campuses and led to more than 2,400 arrests, The Associated Press reported.

"When you're going to Columbia, you know you're going to an institution which has an honored place in the history of American protest," said Mark Naison, professor of history and African and African American studies at Fordham University in New York and a participant in the 1968 demonstrations.

"Whenever there is a movement, you know Columbia is going to be right there," Naison told AP.

Sara M, who requested anonymity, is a freshman at Fordham's Bronx campus. On Wednesday, she went to Fordham's Lincoln Center campus in Manhattan and joined protesters.

"I went because we should protest any war," she told China Daily, but "especially against what is happening in Gaza."

She joined protesters in a building where they had erected tents, but left when the school announced demonstrators could be arrested. On Wednesday evening, police made 15 arrests after clearing the campus of demonstrators at the request of the university.

A doctoral student in the humanities program at the University of Maryland in Baltimore, who asked to remain anonymous, told China Daily: "I understand the concern and anger of these young students about the humanitarian disaster, but I don't think they will get anywhere by camping out like this in protest."

She said in a few years they might view their fervor and quest for justice as "ridiculous". "As I get older and see more and more, including (President Joe) Biden saying he won't change his Israel policy, I find what I learn in textbooks and what I see in reality to be very misaligned," she added.

Quito Ziegler, a humanities professor at the School of Visual Art in New York, said: "I think it's atrocious that the administrations of these schools are calling the police on their own students, who are peacefully protesting issues that are profoundly important to them. This generation of students has inherited a world rife with problems, some of which are now leading to genocide."

A 21-year-old SVA student majoring in animation who asked to remain anonymous said: "It's just very brutal. Millions of people in Gaza are being displaced. It's very ironic for America to call out democratic or undemocratic practices in other countries when it itself exercises very undemocratic actions, such as arresting peaceful protesters and intimidating student protesters. They just arrest students. If colleges are institutions meant to educate, this is not the way to do it."

Protests spread

Pro-Palestinian demonstrations that started in the US have spread across the world to London, Paris, Toronto, Rome, Sydney, Tokyo and Beirut.

College officials' responses to the protests have occurred against a global debate over the US' role in the conflict, while both major US political parties have been jockeying for the moral and political high ground.

After weeks of pro-Palestinian protests on campuses nationwide, threats of arrests and expulsions have caused many to shut down as schools end the academic year this month.

However, protests have lingered at some colleges including the University of Virginia, New York University and the New School in New York.

At the University of Virginia, a small group of protesters that included students, faculty and community members set up an encampment on the Charlottesville campus.

They sang songs, read poetry and painted signs to protest "Israel's war in Gaza". However, the peaceful protest ended on Saturday when state police stormed the encampment. Photos on social media showed police in tactical gear with riot shields using tear gas and force to disperse the protesters. At least 25 pro-Palestinian demonstrators were arrested on Saturday, The Washington Post reported.

After the encampment was cleared, police began to push against a growing crowd of protesters, some of whom had come out to support the original demonstrators, and others who were there to witness the scene unfold. Police indiscriminately sprayed tear gas into the crowd, according to the Daily Progress newspaper.

Meanwhile, early on Friday morning, police cleared two pro-Palestinian encampments and arrested student demonstrators at New York University. Student demonstrators had been sleeping in tents inside a New School building and on sidewalks outside NYU buildings in downtown New York.

New York Police Department officials said they acted after the two universities asked for assistance to disperse the illegal encampments. Police arrested 13 people at NYU and 43 at the New School.

NYU President Linda Mills defended the decision to ask for police help, saying that the university leadership "could not tolerate the risk of violence any longer".

In explaining her decision, Columbia President Minouche Shafik said she asked police to end the demonstrations as the protests had pushed the university to the brink.

Divestment demands

Pro-Palestinian demonstrators across the US have accused Israel of committing genocide against Palestinians. However, Jewish students who support Israel and its right to defend itself against Hamas say the protests have made them afraid to walk freely on campus.

Some said denunciations of Zionism and calls for a Palestinian uprising are an attack on the Jewish people.

Many of the pro-Palestinian student demonstrators have called for their universities to make transparent all financial holdings and divest from companies and funds they believe are profiting from or supporting Israel and its policies.

They have also demanded an "amnesty" for students and faculty members who have been disciplined by their schools as a result of protest action.

However, experts have warned that divestment is virtually impossible. Universities probably have very few if any direct ties to companies that are based in Israel or are weapons manufacturers, they said.

Nicholas Dirks, the former chancellor of the University of California, Berkeley, told CNN: "The economy is so global now that even if a university decided that they were going to instruct their dominant management groups to divest from Israel, it would be almost impossible to disentangle".

Many of the protests stopped short of physical confrontations, but clashes included a violent attack last week by pro-Israel protesters at the University of California, Los Angeles, while racist taunts and abuse were hurled by white students at protesters at the University of Mississippi.

New York police arrested 282 people on Tuesday night during crackdowns at Columbia University and the City College of New York. Of those, 74 faced misdemeanor or more serious charges and another 16 had outstanding warrants, prosecutors said. About half of those arrested had no affiliation with either school.

Rights versus wrongs

During the demonstrations, schools have weighed up free expression, including the right to peaceful protest, against safety risks and ensuring that protests don't encroach upon the rights of students, faculty and staff members.

Now many schools are wrestling with how to handle possible student protests during graduation ceremonies. Some schools plan to set up designated areas for protests to allow ceremonies to go forward without quashing free speech. School administrations are also hiring extra security and screening attendees at venues, AP reported.

A graduation ceremony at the University of Michigan in Ann Arbor on Saturday was briefly interrupted by dozens of pro-Palestinian protesters. As the ceremony got underway, about 75 protesters — many in kaffiyeh, a headdress worn by Arabs, and graduation caps — unfurled Palestinian flags and posters as they marched toward the stage chanting: "Regents, regents, you can't hide! You are funding genocide!"

One demonstrator carried a banner reading, "No universities left in Gaza". Others held Palestinian flags while others waved Israeli flags.

Campus police prevented the protesters from reaching the stage. US Navy Secretary Carlos Del Toro paused a few times during his remarks at the ceremony, saying at one point, "Ladies and gentlemen, if you can please draw your attention back to the podium."

A plane flew over the ceremony trailing a banner that said: "Divest from Israel now! Free Palestine".Another plane had a different message: "We stand with Israel. Jewish lives matter".

Officials said no one was arrested, and the protest did not seriously interrupt the nearly two-hour event, which was attended by tens of thousands of people.

Graduations rethink

At least two schools have altered their graduation ceremonies in light of the ongoing protests.

The University of Vermont announced on Friday that Linda Thomas-Greenfield, the US ambassador to the United Nations, would not deliver a commencement address scheduled for later this month.

The University of Southern California canceled its valedictorian commencement speech and appearances by celebrity speakers and its "main stage" commencement ceremony, citing the possibility of disruptions. On Friday, the university announced a "Trojan Family Graduate Celebration "in the Los Angeles Memorial Coliseum for graduates to attend instead.

To head off possible disruptions of final exams and graduation ceremonies, a number of universities have struck deals with protesters, including Brown in Rhode Island, Northwestern in Illinois and Rutgers in New Jersey, CBS News reported on Saturday.

The deals included commitments by universities to review their investments in Israel, but with no promises about changing such investments.

"I think for some universities, it might be just a delaying tactic to defuse the protests," Ralph Young, a history professor who studies American dissent at Temple University in Philadelphia, told CBS News. "The end of the semester is happening now. And maybe by the time the next semester begins, there is a cease-fire in Gaza."

Columbia University is rethinking its commencement ceremony planned for May 15, according to a source at the university, NBC News reported.

Administrators indicated to student leaders at a meeting that they were unsure about the ceremony being held at the main campus in Manhattan because of security concerns.

A student representative said Columbia's administration was primarily concerned about outside protesters and was seeking an alternative venue.

The student leaders told the university that many students were concerned about school president Shafik speaking at the ceremony. "Her presence would be the cause of a lot of upset," one of them told NBC News.

In her message to the Columbia University community on why she requested police help to end the protests, Shafik said the students had paid a "high price", and missed out on the final days of the year in classrooms and residence halls.

"For those of you who are seniors, you're finishing college the same way you started: online," she said.

Xin Wen in Beijing contributed to this story.