A sit-in at New York City's Trump Tower is underway as protesters gathered to demand the release of Mahmoud Khalil, a Palestinian activist detained over the weekend by federal immigration agents.

Police have arrested dozens of demonstrators from a Jewish group who filled the lobby of Trump Tower to denounce the immigration arrest of Mahmoud Khalil, a pro-Palestinian activist who helped lead protests against Israel at Columbia University.

The NYPD said nearly 100 people were arrested Thursday after a group of protesters entered Trump Tower in New York City to support Mahmoud Khalil.