Dozens of protesters have been arrested at Yale University as demonstrations against the war in Gaza rock US campuses. Protesters occupying a square ignored multiple requests to leave, the Ivy League institution told the BBC. Meanwhile, Columbia University students were told to attend classes virtually Monday after over 100 arrests were made during protests there last week. The White House has condemned alleged incidents of antisemitism at Columbia. The ongoing protests have raised concerns about the safety of Jewish students at schools across the country. Since the Oct. 7 attack on southern Israel by Hamas gunmen, debates and fights about the Middle East and free speech have erupted on college campuses across the country, and tensions are now rising at major universities. Protest "encampments" have also sprung up at other universities across the country, including the University of Michigan, the Massachusetts Institute of Technology, Emerson College and Tufts. Students on both sides say there has been a rise in both antisemitic and Islamophobic incidents. At Yale, many protesters have been calling for the university to cut its investments in weapons manufacturers. Sunday marked the third night that protesters set up tents on an encampment at Beinecke Plaza, according to student newspaper Yale Daily News. The university said the protests grew to involve "several hundred people" over the weekend. An invitation to protesters to meet the university"s investment body is said to have been declined. Although some followed a request to leave, other protesters ignored "multiple requests", leading to 47 arrests by campus police, the university said. Similarly, New York city police were called onto the campus of Columbia last week and arrested dozens of protesters also calling for divestment. The demonstration, which also included students camping on a campus lawn, coincided with Columbia President Minouche Shafik journeying to Capitol Hill to testify before a congressional committee on the university"s efforts to tackle antisemitism. The daughter of Minnesota politician Ilhan Omar was among those arrested and accused of breaking security rules. Columbia held classes virtually on Monday, the start of the Jewish holiday of Passover, according to a statement from Dr. Shafik that highlighted instances of "intimidating and harassing behavior", including antisemitism. Students who do not live on campus were advised to stay away. In Monday"s statement, Dr. Shafik said tensions on campus had been "exploited and amplified by individuals who are not affiliated with Columbia who have come to campus to pursue their own agendas". A working group had been created to "try to bring this crisis to a resolution", she added. US media earlier reported that a rabbi associated with the university had sent a message to 300 Jewish students advising them to keep away from campus until the situation "dramatically improved". Alleged incidents of antisemitism across the US have been condemned by the White House. In a statement marking Passover on Sunday, President Joe Biden urged Americans to speak out "against the alarming surge of antisemitism" in US schools, communities and online. "Silence is complicity," he said. "This blatant antisemitism is reprehensible and dangerous — and it has absolutely no place on college campuses, or anywhere in our country." The White House deputy press secretary said students had the right to peaceful protest, but denounced "calls for violence and physical intimidation targeting Jewish students". The protests in New York have also attracted the attention of several lawmakers, including representatives Jared Moskowitz, Josh Gottheimer, Dan Goldman and Kathy Manning — all Democrats. In a letter posted online, North Carolina Republican Virginia Foxx — the chair of the House Education Committee — wrote that "Columbia"s continued failure to restore order and safety" constitutes a breach of obligations on which federal assistance is contingent and must be "immediately rectified." Former President Donald Trump, who is in New York City for his trial, said on his Truth Social social media platform that the police who have shut down the area around the courthouse "like a drum" should be sent to Columbia. "The university would then not have to shut down," he wrote. Earlier, videos posted online appeared to show some protesters expressing support for the Hamas attack on Israel. As well as the protests at universities, there have also been wider demonstrations in the US over the events in Gaza. Pro-Palestinian protesters recently blocked major roads across the country, restricting access to airports including Chicago"s O"Hare International and Seattle-Tacoma International, as well as the Golden Gate Bridge in San Francisco and Brooklyn Bridge in New York. — BBC