A group of pro-Israel students at Cooper Union was locked inside a library Wednesday as a pro-Palestine protest took place outside, according to reports. Those who were in the Manhattan library throughout the demonstration told CBS New York that school staff decided to lock them in out of safety concerns as demonstrators chanted and banged on the doors. “It was tense. People were nervous,” one student said. “They were specifically acting very aggressive in those spaces where outwardly Jewish students were sitting.” A representative for the school said the students chose to remain in the library—which was closed for around 20 minutes—until the protest ended. One student said they were eventually escorted out by security. Representatives from the pro-Palestine protest said in a statement that the protest was against Cooper Union itself over the school’s “one-sided stance and participation in the occupation of Palestine” and that they do not condone antisemitism. At a news conference on Thursday morning, John Chell, chief of patrol for the New York Police Department, stated police officers had attended the protest in plainclothes, as requested by the college. “There was no direct threat. There was no damage, and there was no danger to any students in that school.” he said.