Police officers carrying zip ties and riot shields stormed a Columbia University building being occupied by pro-Palestinian protesters, streaming in through a window late Tuesday and arresting dozens of of people. The protesters had seized the administration building, known as Hamilton Hall, more than 20 hours earlier in a major escalation as demonstrations against the Israel-Hamas war spread on college campuses nationwide. A statement released by a Columbia spokesperson said officers entered the campus after the university requested help. A tent encampment on the school's grounds began nearly two weeks ago to protest the Israel-Hamas war.