The US institution says it has banned attackers responsible for spraying a hazardous chemical on pro-Palestine rally.

In a statement sent via email to Columbia students and faculty members on Monday night, interim provost Dennis A Mitchell said the alleged perpetrators had been banned from campus following “what appears to have been serious crimes, possibly hate crimes”.

“The University received additional information Sunday night. As a result, the alleged perpetrators identified to the University were immediately banned from campus while the law enforcement investigation proceeds,” Mitchell wrote, according to the US media outlet Rolling Stone.

Mitchell said the university condemned “in the strongest possible terms any threats or acts of violence” directed towards its community and described the incident as “deeply troubling”.

Columbia has asked anyone in possession of photos, videos or any other evidence of the event to present it to the police department.

The university did not clarify whether those banned were students, or how many individuals were involved.

The Columbia Spectator, a student newspaper, reported that the protesters were attacked during a “divestment now” rally on the steps of Low Library on Friday. At least three students required medical attention while others reported physical symptoms such as burning eyes, headaches, and nausea.

A police spokesman told The New York Times that no arrests had been made.

According to 18-year-old freshman student Maryam Iqbal, interviewed by Rolling Stone, peaceful protesters were sprayed by at least two men with a foul-smelling liquid.

Another student, Layla Saliba, a 24-year-old Palestinian American, said the two men called some of the protesters “terrorists.” She added that they were “especially aggressive” towards students holding up signs saying “Jews for cease-fire”, calling them “self-hating Jews.”

Saliba told the American magazine that she kept vomiting and could still smell the odour on herself after a dozen showers.

Tensions have surged at some American universities since the Palestinian group Hamas launched a surprise attack on Israel on October 7 and Israel responded with a declaration of war.

Members of Jewish anti-Zionist organisation Jewish Voice for Peace have reported being spat on and witnessing harassment on campus for their views.

Omar Shakir, the Israel and Palestine director for Human Rights Watch (HRW), said a speaking arrangement had been cancelled by the US university twice due to the lack of “security approvals”.

The Ivy League institution in November suspended student groups Students for Justice in Palestine and Jewish Voice for Peace for allegedly violating school policies for “threatening rhetoric and intimidation”.