Rubio’s letter notified DHS that he had revoked both targets’ visas, setting in motion plans for U.S. Immigration and Customs Enforcement to arrest and attempt to deport them, according to a senior DHS official and another U.S. official who spoke on condition of anonymity to describe how the operation against Khalil took shape.

Some protesters held signs that read "Fight Nazis not students," "Free Mahmoud free Palestine" and "You can’t deport a movement."