Khalil’s arrest could have a chilling effect on on- and off-campus protests involving people who aren’t citizens, said Columbia University immigration law professor Elora Mukherjee. Already, she said, it had provoked panic and fear among immigrant students on campus.

Palestine activists of engaging in “pro-terrorist, anti-Semitic, anti-American activity.” A judge has temporarily blocked Khalil’s deportation.

Mahmoud Khalil's detention appears to be one of the first efforts by Trump to fulfill his promise to seek the deportation of some foreign students involved in the pro-Palestinian protest movement.