A prominent Palestinian activist who helped lead Columbia University’s student encampment movement was arrested on Saturday night by federal immigration authorities who claimed they were acting on a State Department order to revoke his green card, according to his attorney.

Mahmoud Khalil was at his university-owned apartment, blocks from Columbia University’s main campus in New York, when several Immigration and Customs Enforcement (ICE) agents entered the building and took him into custody, his attorney, Amy Greer, told the Associated Press. One of the agents told Greer by phone that they were executing a State Department order to revoke Khalil’s student visa. When Greer informed them that Khalil, who graduated last December, was in the U.S. as a permanent resident with a green card, the agent responded that they were revoking that too, according to the lawyer.

The arrest comes as Donald Trump vows to deport foreign students and imprison “agitators” involved in protests against Israel’s war on Gaza. The administration has placed particular scrutiny on Columbia, announcing Friday that it would be cutting $400 million in grants and contracts due to what it describes as the university’s failure to address ’antisemitism’ on campus.

Authorities declined to tell Khalil’s wife, who is eight months pregnant, why he was being detained, Greer said. Khalil has since been transferred to an immigration detention facility in Elizabeth, New Jersey. “We have not been able to get any more details about why he is being detained,” Greer told the AP. “This is a clear escalation. The administration is following through on its threats.”

A Columbia spokesperson stated that law enforcement agents must produce a warrant before entering university property but declined to say if the school had received a warrant for Khalil’s arrest. Messages seeking comment were left with the Department of State, the Department of Homeland Security (DHS), and ICE.

Khalil had become one of the most visible faces of the pro-Palestinian movement at Columbia. As students erected tents on campus last spring, Khalil was chosen as a negotiator on behalf of the protesters and frequently met with university administrators. When classes resumed in September, he told the Associated Press that demonstrations would continue: “As long as Columbia continues to invest and to benefit from Israeli apartheid, the students will continue to resist.”

An immigration court can revoke a green card, but government departments do not have that power. Last week, Axios reported that Secretary of State Marco Rubio intends to revoke visas from foreign nationals deemed to ’support Hamas or other terrorist groups,’ using artificial intelligence (AI) to identify individuals.

Khalil was among several students investigated by Columbia’s newly created Office of Institutional Equity, a university disciplinary committee examining individuals who have expressed criticism of Israel, according to records shared with the AP. In recent weeks, the committee has sent notices to dozens of students for activities ranging from sharing social media posts supporting Palestinians to joining “unauthorized” protests.

“I have around 13 allegations against me, most of them are social media posts that I had nothing to do with,” Khalil said last week. After refusing to sign a non-disclosure agreement, Khalil said the university threatened to block him from graduating. However, when he appealed the decision through a lawyer, the university eventually backed down. “They just want to show Congress and right-wing politicians that they’re doing something, regardless of the stakes for students,” Khalil said. “It’s mainly an office to chill pro-Palestine speech.”

Columbia students initiated the tent encampment protests at their Manhattan campus last spring, a movement that spread to dozens of universities across the U.S. At Columbia and many other institutions, administrators called in local police, leading to the arrests of hundreds of students.

Murad Awawdeh, president and CEO of the New York Immigration Coalition, condemned the arrest in a statement on Sunday afternoon. “Targeting a student activist is an affront to the rights of Mahmoud Khalil and his family. This blatantly unconstitutional act sends a deplorable message that freedom of speech is no longer protected in America. Furthermore, Khalil and all people living in the United States are afforded due process. A green card can only be revoked by an immigration judge, showing once again that the Trump administration is willing to ignore the law in order to instill fear and further its racist agenda,” Awawdeh said. “DHS must immediately release Khalil.”