Border czar calls detained Columbia activist Mahmoud Khalil a 'national security threat'

Trump administration border czar Tom Homan on Wednesday called Mahmoud Khalil -- the pro-Palestinian activist arrested by Immigration and Customs Enforcement -- "a national security threat," citing student protests at Columbia University that called for the institution to cut ties with Israel over its war in Gaza.

"When you are on campuses -- I hear 'speech,' 'freedom of speech,' 'freedom of speech' -- can you stand at a movie theater and yell fire? Can you slander? Free speech has limitations," Homan said during an appearance in Albany, New York.

"Coming to this country either on a visa or becoming a resident alien is a great privilege, but there are rules associated with that. You might have been able to get away with that stuff in the last administration, but not this administration," Homan said.

At a hearing Wednesday afternoon, a federal judge set an expedited briefing schedule for Khalil -- who possesses a green card and has not been charged with a crime -- saying, "There is some need for speed here."

Khalil is set to appear before an immigration judge on March 27 in Louisiana.

Khalil's attorneys said the former Columbia student is a lawful permanent resident with no criminal record, but they declined Judge Jesse Furman's invitation to immediately argue the merits of the case. Instead, Khalil's attorneys said they would file an amended petition by Thursday evening.

The government said it would argue Khalil's petition should be heard either in New Jersey, where he was taken after his arrest Saturday night, or in Louisiana, where he is being held.

With activists like actress Susan Sarandon looking on in court and protesters chanting outside, the judge ordered a phone call be arranged for Khalil on Wednesday after his attorneys argued access to their client is "severely limited."

"We have literally not been able to confer with our client once since he was taken off the streets," Khalil's attorney Ramzi Kassem said.

Khalil is currently being held in Louisiana after being detained in New York earlier this week. His legal team is asking the court to order the government to return him to New York while his legal fight plays out.

Khalil's wife, who is 8 months pregnant, said the couple have been excitedly preparing for the arrival of their baby.

"Mahmoud has been ripped away from me for no reason at all. I am pleading with the world to continue to speak up against his unjust and horrific detention by the Trump administration," she said in a statement to ABC News on Wednesday.

"Six days ago, an intense and targeted doxxing campaign against Mahmoud began. Anti-Palestinian organizations were spreading false claims about my husband that were simply not based in reality. They were making threats against Mahmoud and he was so concerned about his safety that he emailed Columbia University on March 7th. In his email, he begged the university for legal support," she said.

She said Columbia University never responded to that email and he was arrested a day later.

President Donald Trump's administration has alleged that Khalil -- who was a leader of the pro-Palestinian encampment protests on Columbia's campus -- was a supporter of Hamas. Baher Azmy, one of Khalil's lawyers, called his client's alleged alignment with Hamas "false and preposterous."

"Setting aside the false and preposterous premise that advocating on behalf of Palestinian human rights and to plead with public officials to stop an ongoing genocide constitutes alignment with Hamas, his speech is absolutely protected by the Constitution, and it should be chilling to everyone that the United States government could punish or try to deport someone because they disapprove of the speech they're engaged in," Azmy told ABC News on Monday.

Authorities have not charged Khalil with a crime and the administration has not provided any evidence showing Khalil's alleged support for the militant group.

The Trump administration said it has the authority to remove Khalil under the Immigration and Nationality Act.

"Under the Immigration and Nationality Act, the secretary of state has the right to revoke a green card or a visa for individuals who serve, or are adversarial to the foreign policy and the national security interests of the United States of America," White House press secretary Karoline Leavitt said Tuesday. "Mahmoud Khalil was an individual who was given the privilege of coming to this country to study at one of our nation's finest universities and colleges and he took advantage of that opportunity, of that privilege, by siding with terrorists, Hamas terrorists."

Attorney Amy E. Greer said Khalil's detention in Louisiana is a "blatantly improper but familiar tactic designed to frustrate the New York federal court's jurisdiction."

Khalil's arrest has prompted protests calling for his release. Fourteen members of Congress have also signed a letter demanding his release.

Khalil will have to show at the immigration hearing on March 27 why he should not be removed from the U.S.

ABC News' Armando Garcia, James Hill, Laura Romero, Ely Brown and Mark Crudele contributed to this report.