NEW YORK — A federal judge has temporarily blocked the deportation of Mahmoud Khalil, a pro-Palestinian activist and Columbia University graduate who was detained by ICE agents over the weekend in New York, while he weighs the petition challenging Khalil’s arrest.

The judge’s decision comes as several hundred protesters massed Monday in Lower Manhattan to demand the release of Khalil, who was detained on Saturday.

“He was arrested for speaking out against genocide,” said Marian Osman, one of the organizers. “We have a right to free speech. Political speech is protected speech in this country.”

After President Donald Trump posted that Khalil would not be the last pro-Palestinian demonstrator arrested, Osman pledged protesters would not be intimidated.

“We are just getting started,” she said. “I do think protesters should be scared. I think protesters should be upset and angry.”

Demonstrators carried signs that said, “No political prisoners in the United States” and “Release Mahmoud Khalil.”

The arrest of Khalil, a green card holder, also prompted the institution to ramp up security measures in an attempt to thwart any protests.

SEE ALSO | Trump administration cancels $400 million worth of grants and contracts to Columbia University

Columbia public safety has restricted access to three gates on its Morningside Heights campus and it is only open to students, registered guests and alumni.

An attorney for Khalil said Monday afternoon that he is currently being held at a detention facility in Jena, Louisiana. He has not been formally charged with a crime.

His 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.

The Council on American-Islamic Relations, a national Muslim civil rights advocacy group, said Monday that it is working with Khalil’s lawyer and called for his immediate release.

Khalil “is a lawful permanent resident of our nation who has not been charged with or convicted of a single crime,” the Washington-based group said in a statement. “The Department of Homeland Security’s lawless decision to arrest him solely because of his peaceful anti-genocide activism represents a blatant attack on the First Amendment’s guarantee of free speech, immigration laws, and the very humanity of Palestinians.”

Some students told our sister station, ABC7 Eyewitness News in New York, they are outraged.

“I think we need to protect the integrity of this institution as a place where people can feel comfortable sharing all opinions on these subjects,” said a Columbia student named Emma. “And I think this is a violation of academic and of human integrity broadly.”

Khalil filed a petition in federal court in Lower Manhattan, claiming it has no basis for his detention, other than the federal government is looking to quiet an outspoken activist.

It names Homeland Security Secretary Kristi Noem, Attorney General Pam Bondi, acting ICE New York field office director William Joyce and acting ICE Director Caleb Vitello as respondents.

A federal judge on Monday then temporarily blocked Khalil’s deportation while he weighs the petition. A court appearance is scheduled for Wednesday morning.

Last week, the Trump administration announced that it was cutting $400 million in grants and contracts for Columbia University after saying the institution failed to fight antisemitism on campus.

“I think that’s going to hurt people who have absolutely nothing to do with this,” said a Columbia student named Brian.

The Jewish student, who fears retribution, says the government’s decision to pull funding is misguided, but says antisemitism is a deep-seeded issue at the university.

“There’s like an embedded systemic problem at Columbia with administrators, faculty and professors,” Brian said.

He thinks ICE should go after them, and not the grad student they did arrest, but another student thinks the arrest was the necessary.

“He has been openly antisemitic. He has engaged in just objective wrongdoing, violating university conduct and rules,” the student said. “You know, if the administration doesn’t do anything, then it is up to our federal government to show up and hold the student accountable.”

There is concern that ICE could return to the campus after the Secretary of State Marco Rubio said “we will be revoking the Visas and/or green cards of Hamas supporters in America so they can be deported.”

Restrictions at additional college campuses are expected after Barnard College announced it would also be increasing security measures on Monday “due to active concerns for violence.”

Khalil is the first person known to be detained for deportation under Trump’s promised crackdown on students protesting the war in Gaza. He 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.

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.

The Associated Press contributed to this report.