Large numbers of New York City police officers began entering Columbia University late on Tuesday as dozens of pro-Palestinian Arab protesters remained on the campus, The Associated Press reported.

Shortly before officers entered the campus, the New York Police Department received a notice from Columbia authorizing officers to take action, a law enforcement official told AP.

After entering the campus, a contingent of police officers approached Hamilton Hall, the administration building that students began occupying in the morning.

At least 100 people were reportedly arrested.

“Walk away from this situation now and continue your advocacy through other means,” New York City Mayor Eric Adams advised the Columbia protesters on Tuesday afternoon. “This must end now.”

The White House earlier on Tuesday condemned the standoffs at Columbia and California State Polytechnic University, Humboldt, where protesters had occupied two buildings until officers with batons intervened overnight and arrested 25 people. Columbia University has seen an uptick in pro-Palestinian Arab protests in recent days.

The latest protests at Columbia began last Wednesday, when anti-Israel protesters set up a tent city on the campus grounds.

Last Thursday, more than 100 people were arrested by New York Police Department officers on a preliminary charge of criminal trespass, as police entered Columbia University to disperse a the pro-Palestinian Arab protest, but it has since continued and grown more explicitly antisemitic.

On Saturday night, the Chabad rabbi of Columbia University and a group of Jewish students were forced to leave the university campus for their own safety during a pro-Hamas demonstration.