A Palestinian graduate student at Columbia University, Mahmoud Khalil, was arrested by US Department of Homeland Security (DHS) agents at his university dormitory on Saturday, the Student Workers of Columbia union said. Khalil is a student at Columbia’s School of International and Public Affairs and was a central figure in last year’s pro-Palestinian demonstrations on campus.

Khalil was a chief negotiator between student protesters and Columbia administrators, especially after demonstrators have occupied an academic building and established a tent encampment in April 2023. Even if he did not participate in the occupation, he also served as a facilitator for dialogue between protest leaders and school officials.

The arrest seems to be among the earliest moves by the administration of President Donald Trump upon his recent reelection, in following through on a promise to remove foreign students from pro-Palestinian protests from the United States. The pro-Palestinian protests, provoked by the Hamas attack on Israel on October 7 and consequent Israeli defense forces action on Gaza, also caused disturbance at various US universities.

Though he is a legal resident of the US and married to a citizen, Khalil spent the weekend in detention. His wife refused comment, and Columbia University said it couldn’t lawfully release details of individual students.

The Trump administration, DHS, and the State Department also did not reply to requests for comments explaining the charges against Khalil. The day before his arrest, hours earlier, Khalil had complained to Reuters that he was being harassed by the government for talking to the press.