Shelter-in-place alert issued at Columbia University as police raid campus

A student protester waves a Palestinian flag above Hamilton Hall on the campus of Columbia University (Mary Altaffer/AP)

Columbia University issued a shelter-in-place order on Tuesday evening as the New York Police Department descended on the campus in riot gear to dispel protesters.

More than 1,000 protesters have been arrested over the last two weeks on university campuses in Texas, Utah, Virginia, North Carolina, New Mexico, Connecticut, Louisiana, California and New Jersey.