New York City police officers entered the grounds of Columbia University on Tuesday night to arrest and disperse pro-Palestinian protesters who took over a campus building nearly 24 hours earlier and have occupied a tent camp at the Ivy League school for nearly two weeks. Live television images showed helmeted police in tactical gear entering the elite campus in upper Manhattan, which has been the focal point of student protests that have spread to dozens of schools across the U.S. in recent days expressing opposition to Israel's war in Gaza. At post-secondary institutions across the U.S., student demands include that their school severs any business or academic links to Israel.