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.

Nearly 100 people were arrested Thursday after staging a sit-in at Trump Tower in New York City, the NYPD said. It started at around 11:30 a.m. Thursday, police said.According to police, roughly 150 people dressed in civilian clothes entered Trump Tower just before noon.

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.