New Haven Police Department said about 45 protesters were detained at Yale and charged with misdemeanour trespassing after blocking traffic and refusing to leave.

There were no reports of any violence or injuries, and all were released on condition they would appear in court later.

The protesters want the world-famous university to sever any investments in defence companies that sell to Israel.

Meanwhile, Columbia told students to stay at home in a bid to ease tensions at the New York City university following the arrests of more than 100 people last week.

Its president, Nemat Minouche Shafik, denounced antisemitic behaviour and harassment she said had occurred on university grounds.

"These tensions have been exploited and amplified by individuals who are not affiliated with Columbia who have come to campus to pursue their own agendas," she said in a statement.

Some protesters have set up camp at Columbia, while demonstrations have also been going on at Boston's Emerson College and nearby MIT, as well as the University of Michigan and University of North Carolina.

President Biden condemned antisemitism on campuses in a statement on Sunday to mark the Jewish festival of Passover.

"Even in recent days, we've seen harassment and calls for violence against Jews," said the US president.

"This blatant antisemitism is reprehensible and dangerous - and it has absolutely no place on college campuses, or anywhere in our country."

Elie Buechler, a rabbi at Columbia, sent a WhatsApp message to Jewish students on Sunday urging them to leave the campus.

"It deeply pains me to say that I would strongly recommend you return home as soon as possible and remain home until the reality in and around campus has dramatically improved," he said.

New York City Police said on Monday they would not enter Columbia grounds unless a crime was taking place as the university is private property.

Deputy Commissioner Michael Gerber told reporters the university didn't want officers stationed on campus, but there was a large police presence on the streets outside.

"Any kind of violence is not going to be tolerated, any kind of property damage is not going to be tolerated," he said.

"That includes harassment, or threats, or menacing or stalking, or anything like that that's not protected by the First Amendment."

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Deputy Commissioner Tarik Sheppard said there had so far been no "credible threats to any particular group of individuals coming from this protest or any other".

Protest organisers at Columbia said they were being portrayed unfairly and claimed the media were focussing on a few "inflammatory individuals" who did not represent their movement.

They want the university to cut ties with corporations profiting from Israel's actions in Gaza, transparency on its financial investments, and an amnesty for students and staff disciplined for supporting the Palestinian cause.