Federal immigration authorities arrested a Palestinian activist Saturday who played a prominent role in Columbia University’s protests against Israel, a significant escalation in the Trump administration’s pledge to detain and deport student activists.

Mahmoud Khalil, who recently completed a graduate program at Columbia, has legal permanent residency, his lawyer said.

Mahmoud Khalil, a student at Columbia’s School of International and Public Affairs, was taken into custody at his university residence by Department of Homeland Security agents, according to the Student Workers of Columbia union.