(NEW YORK) -- The arrest of Palestinian activist Mahmoud Khalil was a "targeted, retaliatory detention and attempted removal of a student protestor because of his constitutionally protected speech," his attorneys said Thursday in a new petition seeking his immediate release.
Khalil, a leader of the Columbia University encampment protests last spring, was detained on March 8 and is being held in Louisiana as of Thursday.
He possesses a green card and has not been charged with a crime.
Officials from President Donald Trump's administration have said Khalil was detained for his purported support of Hamas. But Baher Azmy, one of Khalil's lawyers, called his client's alleged alignment with Hamas "false and preposterous."
His lawyers argued in their petition that Secretary of State Marco Rubio had determined that Khalil's presence in the United States would have potentially serious foreign policy consequences based on lawful activity -- namely his participation in protests and his statements about Israel.
"Neither Secretary Rubio nor any other government official has alleged that Mr. Khalil has committed any crime or, indeed, broken any law whatsoever," the amended petition said.
"The Rubio Determination and the government's subsequent actions, including its ongoing detention of Mr. Khalil in rural Louisiana, isolating him from his wife, community, and legal team, are plainly intended as retaliation and punishment for Mr. Khalil's protected speech and intended to silence, or at the very least restrict and chill, his speech now and in the future, all in violation of the First Amendment," it continued.
His lawyers conceded Khalil is "an outspoken student activist" who called Israel's actions in Gaza "genocide," but they also said he has been "committed to peaceful protest."
Khalil was taken from New York to New Jersey following his arrest. He was later transferred to Louisiana. The complaint described a process in which "Mr. Khalil felt as though he was being kidnapped. He was reminded of prior experience fleeing arbitrary detention in Syria."
The petition claims that the arrest violated Khalil's First and Fifth Amendment rights, as well as the Administrative Procedure Act.
At least 98 people were arrested at a protest in the lobby of Trump Tower in New York City calling for Khalil's release earlier in the day on Thursday.
Separately, Columbia University announced Thursday that students who occupied the campus' Hamilton Hall during pro-Palestinian protests last spring have been expelled, been suspended for several years or had their degrees temporarily revoked.
Khalil is set to appear before an immigration judge on March 27.