The action came less than a week after Mahmoud Khalil, a recent Columbia graduate and a prominent figure in campus demonstrations, was arrested.

The U.S. Justice Department said on Friday it was looking into what it said were possible violations of terrorism laws during protests over the Gaza war at Columbia University, putting fresh pressure on the epicenter of last year's nationwide anti-Israel activism.

Columbia University announced punishments, including expulsions and suspensions, for students who occupied Hamilton Hall in a pro-Palestinian protest last year.