On the evening of April 30, hundreds of police officers in New York City entered Columbia University and arrested dozens of pro-Palestinian demonstrators who had occupied campus buildings.

The arrest marked the culmination of a standoff that began more than a week ago, when students pitched tents on the lawn in the center of the campus and demanded that the university divest from companies that profit from Israel.

As they did, protesters behind barricades blocking nearby streets chanted “Palestine will be free,” “Let students leave,” and “NYPD-KKK.” It is unclear how many people are affiliated with the university. There were no immediate reports of injuries.