NEW YORK (AP) — Federal immigration authorities arrested a Palestinian graduate student who played a prominent role in last spring’s anti-Israel protests at Columbia University, according to his attorney.

Mahmoud Khalil was inside his university-owned residence Saturday night near Columbia’s Manhattan campus when several Immigration and Customs Enforcement agents entered the building and took him into custody, his attorney, Amy Greer, told The Associated Press.

Greer said she spoke by phone with one of the ICE agents during the arrest, who said they were acting on State Department orders to revoke Khalil’s student visa. Informed by the attorney that Khalil was in the United States as a permanent resident with a green card, the agent said they were revoking that too, according to the lawyer.

The arrest appeared to be among the first known actions under President Donald Trump’s pledge to deport international students who joined the protests against Israel’s war in Gaza that swept college campuses last spring. His administration has claimed participants forfeited their rights to remain in the country by supporting Hamas, a terror organization.

Khalil served as a negotiator for students as they bargained with university officials over an end to the tent encampment erected on campus, a role that made him one of the few student activists willing to share his name and identity.

The authorities declined to tell Khalil’s wife, who is eight months pregnant, whether he was accused of committing a crime, 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 said law enforcement agents must produce a warrant before entering university property, but declined to say if the school had received one ahead of Khalil’s arrest. The spokesperson also declined to comment on Khalil’s detention.

Messages seeking comment were left with the State Department, the Department of Homeland Security and ICE.

The Department of Homeland Security can initiate deportation proceedings against green card holders for a broad range alleged criminal activity, including supporting a terror group. It would ultimately be up to an immigration judge to revoke someone’s permanent resident status, according to Camille Mackler, founder of Immigrant ARC, a coalition of legal service providers in New York.

“This has the appearance of a retaliatory action against someone who expressed an opinion the Trump administration didn’t like,” Mackler said.

Khalil was among those investigated by a new Columbia University office that has brought disciplinary charges against dozens of students who have expressed criticism of Israel, according to records shared with the AP.

Those investigations come as the Trump administration has ramped up scrutiny on Columbia because of what the government describes as the Ivy League school’s failure to squelch antisemitism on campus. On Friday, federal agencies announced they would be cutting $400 million in grants and contracts from the university.

The allegation against Khalil focused on his involvement in the Columbia University Apartheid Divest group, claiming he had helped organize an “unauthorized marching event” that glorified Hamas’ Oct. 7, 2023, attack and played a “substantial role” in the circulation of social media posts criticizing Zionism.

“I have around 13 allegations against me, most of them are social media posts that I had nothing to do with,” Khalil told the AP last week.

“They just want to show Congress and rightwing politicians that they’re doing something, regardless of the stakes for students,” he added. “It’s mainly an office to chill pro-Palestine speech.”