NEW YORK (AP) — The pro-Palestinian demonstration that paralyzed Columbia University ended in dramatic fashion late Tuesday, with police carrying riot shields swarming the Ivy League campus, bursting into an administration building protesters took over the previous night and making dozens of arrests.

A statement released by a Columbia spokesperson said New York City officers entered the campus after the university requested help. A tent encampment on the school’s grounds to protest the Israel-Hamas war was cleared, along with Hamilton Hall where a stream of officers used a ladder to climb through a second-floor window. Protesters seized the hall about 20 hours earlier.

“After the University learned overnight that Hamilton Hall had been occupied, vandalized, and blockaded, we were left with no choice,” the school said. “The decision to reach out to the NYPD was in response to the actions of the protesters, not the cause they are championing. We have made it clear that the life of campus cannot be endlessly interrupted by protesters who violate the rules and the law.”