Columbia University associate of Mahmoud Khalil arrested by DHS

A Columbia University student who co-founded, with Mahmoud Khalil, a university organization called Palestinian Student Union was arrested Monday by Department of Homeland Security agents, his attorney told ABC News.

Mohsen Mahdawi, a permanent resident of the U.S., was arrested and detained after attending his naturalization interview in Vermont.

U.S. District Judge William Sessions subsequently granted Mahdawi's attorneys a temporary restraining order barring the government from moving Mahdawi out of District of Vermont "pending further order" from the court.

At Columbia University, Mahdawi was an "outspoken critic of Israel's military campaign in Gaza and an activist and organizer in student protests on Columbia's campus until March of 2024, after which he took a step back and has not been involved in organizing," according to a habeas petition obtained by ABC News.

Mahdawi's attorneys called his arrest "unlawful" and said it violates the First Amendment.

"Mr. Mahdawi's unlawful arrest and detention comes after Respondents adopted a policy ... to retaliate and punish noncitizens for their speech and expressive conduct related to Palestine and Israel," the attorneys said.

A spokesperson for Immigration and Customs Enforcement referred ABC News to the State Department, which did not immediately respond to a request for comment.

According to his habeas petition, Mahdawi was born and raised in a refugee camp in the West Bank, until 2014 when he moved to the United States. He has been a legal resident for the last 10 years and is expected to graduate from Columbia next month.

In December of 2023, Mahdawi appeared on the TV news show "60 Minutes," where he shared that "as a child, he watched an Israeli soldier shoot and kill his best friend in the West Bank," the petition said.

"Mr. Mahdawi is fearful that, if he loses his lawful permanent resident status and he is removed to the West Bank, he will experience the same harassment, detention, and torture that his family has experienced, and would be in even more danger in light of the campaigns that have targeted and spread lies about him," his attorneys said.

Mahdawi's lawyers believe that, like Khalil, he is being targeted by the Trump administration under Immigration and Nationality Act section 237(a)(4)(C)(i), which assert that the secretary of state can deem a person deportable if they have reasonable ground to believe that the person's presence or activities in the U.S. could have adverse foreign policy consequences.

In a court filing in Khalil's immigration case, DHS submitted a two-page memo from Secretary of State Marco Rubio asserting that the law gives him the power to determine a person is deportable even if their actions are "otherwise lawful."

Rubio wrote that Khalil should be deported because of his alleged role in "antisemitic protests and disruptive activities, which fosters a hostile environment for Jewish students in the United States."

An immigration judge ruled on Friday that Khalil can be deported based on those grounds.

Khalil, a green card holder and permanent legal resident who is married to an American citizen, was arrested by Immigration and Customs Enforcement at his Columbia housing in March after helping lead protests at Columbia over the war in Gaza. He took part in negotiations with school administrators demanding the institution cut ties with Israel and divest from Israeli companies.

Khalil finished his graduate studies at Columbia in December and is set to graduate in the spring.

ABC News' Luke Barr contributed to this report.