By Eliza Shapiro NYTimes News Service
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Federal immigration authorities on Saturday detained a well-known activist who played a major role in Columbia University’s pro-Palestinian student movement last year, his lawyer said Sunday.

The arrest of the activist, a legal permanent resident of the United States, was a significant escalation of President Donald Trump’s crackdown on what he has called antisemitic campus activity.

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The activist, Mahmoud Khalil, is of Palestinian heritage and graduated in December with a master’s degree from the university’s school of international affairs, according to his LinkedIn. His lawyer, Amy Greer, confirmed that he was a green card holder and said the arrest would face a vigorous legal challenge.

“We will vigorously be pursuing Mahmoud’s rights in court, and will continue our efforts to right this terrible and inexcusable — and calculated — wrong committed against him,” Greer said in a statement. The arrest, she said, “follows the U.S. government’s open repression of student activism and political speech.”

Greer said she was not sure of Khalil’s “precise whereabouts,” and that he may have been transferred as far away as Louisiana. Khalil’s wife, an American citizen who is eight months pregnant, tried to visit him at a detention center in New Jersey but was told he was not being held there, Greer said.

U.S. Immigration and Customs Enforcement and the Department of Homeland Security did not immediately reply to a request for comment. On Sunday, Secretary of State Marco Rubio shared a link on social platform X to a news article about Khalil’s arrest and issued a broad promise: “We will be revoking the visas and/or green cards of Hamas supporters in America so they can be deported.”

The immigration agents who detained Khalil told him his student visa had been revoked, Greer said, even though he does not currently hold such a visa. Revoking a green card is quite rare, said Elora Mukherjee, director of the immigrants’ rights clinic at Columbia Law School, and in a vast majority of cases where it does happen, the holder has been accused and convicted of criminal offenses, she said.

If the government was to revoke Khalil’s green card “in retaliation for his public speech, that is prohibited by the First Amendment of the U.S. Constitution,” Mukherjee said, adding that she was still learning details about this particular case.

Jodi Ziesemer, director of the immigrant protection unit at the New York Legal Assistance Group, said the revocation process is typically lengthy. A green card holder can be detained, but not deported, during that process, she said.

Khalil was a fixture at the protests that engulfed Columbia last spring, making the New York City campus the national epicenter of demonstrations against the war in the Gaza Strip. He described his role to reporters as a negotiator and spokesperson for Columbia’s pro-Palestinian group, Columbia University Apartheid Divest.

The Trump administration has made Columbia the first target of its push to punish what the president has deemed elite schools’ failures to protect Jewish students during campus protests.

On Friday, the administration announced that it had canceled $400 million in grants and contracts to the university. In a social media post last week, Trump vowed to punish individual protesters his administration considered “agitators.”

“All federal funding will STOP for any College, School or University that allows illegal protests,” Trump wrote. “Agitators will be imprisoned/or permanently sent back to the country from which they came. American students will be permanently expelled or, depending on the crime, arrested.”

In a statement Sunday, Columbia administrators did not comment directly on the arrest.

“Columbia is committed to complying with all legal obligations and supporting our student body and campus community,” the statement read. “We are also committed to the legal rights of our students and urge all members of the community to be respectful of those rights.”

The arrest drew swift condemnation from some free speech groups, immigrant rights’ activists and politicians on Sunday.

Donna Lieberman, director of the New York Civil Liberties Union, said in a statement that the detention “reeks of McCarthyism.” She added that the arrest was “a frightening escalation of Trump’s crackdown on pro-Palestine speech and an aggressive abuse of immigration law.”

Zohran Mamdani, a New York Assembly member from Queens who is running for New York City mayor, called the detention “a blatant assault on the First Amendment and a sign of advancing authoritarianism under Trump.” Mamdani, a democratic socialist, has faced backlash from some pro-Israel groups for his criticism of Israel.

And Murad Awawdeh, president of the New York Immigration Coalition, said in a statement, “This blatantly unconstitutional act sends a deplorable message that freedom of speech is no longer protected in America.”

But the Columbia Jewish Alumni Association, which has been calling for aggressive action against pro-Palestinian demonstrators, praised Khalil’s detention in a series of social media posts, calling Khalil, without evidence, a “ringleader” of the chaos at Columbia.

This article originally appeared in The New York Times.

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