NEW YORK (AP) — A prominent Palestinian activist who helped lead protests at Columbia University is facing deportation following his arrest by federal immigration agents over the weekend.

Mahmoud Khalil, who graduated from the university in December, was arrested Saturday by Immigration and Customs Enforcement agents. The Department of Homeland Security confirmed the arrest, saying it was a result of President Donald Trump’s executive orders prohibiting antisemitism. He has not been formally charged with a crime.

Khalil’s lawyer, Amy Greer, said the agents who took him into custody at his university-owned home near Columbia initially claimed to be acting on a State Department order to revoke his student visa. But when Greer informed them that Khalil was a permanent resident with a green card, they said they would revoke that documentation instead.

Federal immigration authorities also visited a second international student at Columbia over the weekend and attempted to take her into custody but were prevented from entering the apartment, according to a union representing the student. The woman has not been identified, and it’s not clear what grounds ICE had for the visit.

According to the Student Workers of Columbia, a graduate student union representing the woman, three ICE agents visited her university-owned residence Friday night and attempted to enter without a warrant.

“The agents were rightfully turned away at the door,” the student union said.

Over the weekend, the university circulated guidance to students about its policies for allowing federal authorities on campus. The guidance states that “in general, ICE agents must have a judicial warrant or subpoena to access non-public areas,” including housing.

Secretary of State Marco Rubio said in a message posted Sunday on X that the administration will be “revoking the visas and/or green cards of Hamas supporters in America so they can be deported.”

Khalil’s arrest is the first publicly known deportation effort under Trump’s promised crackdown on students protesting the war in Gaza.

The Republican president has argued that protesters forfeited their rights to remain in the country by supporting the Palestinian terrorist group Hamas that controls Gaza.

Khalil and other student leaders of Columbia University Apartheid Divest have rejected claims of antisemitism, saying they are part of a broader anti-war movement that also counts Jewish students and groups among its members. But the divestment group, at times, has also voiced support for leaders of Hamas and Hezbollah, another Islamist organization designated by the U.S. as a terrorist group.

Khalil is currently being held in an immigration detention center in Louisiana after initially being sent to a facility in New Jersey, according to ICE’s online detainee database, which lists his birthplace as Syria.

It’s unclear when he will have a hearing in immigration court, which is typically the first step in the deportation process. Spokespersons for ICE and DHS did not immediately respond to emails seeking comment Monday.

Columbia University declined to comment on Khalil’s arrest over the weekend. University spokespersons did not immediately respond Monday.

A protest was scheduled for later Monday in front of ICE’s offices in Manhattan.

Khalil was one of the most visible activists in last year’s protests, serving as a negotiator for students who erected a tent encampment on campus. Pro-Israel activists in recent weeks have called on the Trump administration to begin deportation proceedings against him.

Khalil was also among those being investigated by a new Columbia office that has already brought disciplinary charges against dozens of students for their pro-Palestinian activism, according to records shared with The Associated Press.

Khalil received a master’s degree from Columbia’s school of international affairs last semester. His wife, who is an American citizen, is eight months pregnant.

Meanwhile, the Trump administration last week pulled $400 million in federal funding from Columbia because of what it claimed was the Ivy League school’s failure to reign in antisemitism on campus.