Assistant Chief Immigration Judge Jamee Comans, based in the state of Louisiana, said the federal government had met its burden to prove it had grounds to deport Mahmoud Khalil, according to a statement by his attorney.

"Today, we saw our worst fears play out: Mahmoud was subject to a charade of due process, a flagrant violation of his right to a fair hearing, and a weaponization of immigration law to suppress dissent. This is not over, and our fight continues," Khalil's attorney Marc van der Hout said in the statement.

Khalil is not yet scheduled for deportation, and the judge gave his attorneys until April 23 to seek a waiver, the statement added.

The Columbia University student, a prominent face of the protest movement that erupted in response to Israel's war in Gaza, is married to a US citizen.

He was arrested and taken to Louisiana, sparking protests. Several other foreign student protesters have been similarly targeted.

Comans had ordered the government to spell out its case against Khalil, who the government is seeking to deport on the grounds that his protest activities are a threat to national security.

In a letter to the court, US Secretary of State Marco Rubio insisted that Khalil's activism could hurt Washington's foreign policy. But he declined to argue formally that the Algeria-born Palestinian student was Hamas-aligned, as officials have told journalists.

'Campaign of terror'

The undated letter instead referred to Khalil's "participation and roles" in allegedly "anti-Semitic protests and disruptive activities which fosters a hostile environment for Jewish students in the United States."

It made no reference to any alleged crime.

"I would like to quote what you said last time, that there's nothing that's more important to this court than due process rights and fundamental fairness. Clearly what we witnessed today, neither of these principles were present," Khalil told the court according to his legal team.

Homeland Security Secretary Kristi Noem posted to X following the ruling that "when you advocate for violence, glorify and support terrorists [...] and harass Jews [...] you should not be in this country."

The judge in a separate New Jersey case, brought by Khalil's lawyers to contest his detention, held a hearing immediately after the Louisiana proceeding.

Khalil's lawyers will seek to challenge the Louisiana ruling once it has been issued in its entirety, the court heard.

Dozens of high-profile lawyers have joined the case on Khalil's side, framing the proceeding as a test case for freedom of speech and the limits of Trump's power.

Khalil's arrest has triggered outrage from Trump opponents, free speech advocates and some on the political right, who say the case will have a chilling effect on freedom of expression.

"The Trump administration's actions against universities, their researchers and their students have no recent precedent in US history," said Columbia University law professor David Pozen at a teach-in event Friday. "American democracy is in crisis."

Ramya Krishman, a senior staff attorney at Columbia's Knight First Amendment Institute, said "the administration has unleashed, to put it bluntly, a campaign of terror on immigrants in this country. And it seems that no one is safe."

Immigration officers have similarly detained and sought to deport a Tufts University student from Turkey, Rumeysa Ozturk, and Columbia student Yunseo Chung who is a US permanent resident originally from South Korea. 

Their deportations have been blocked for now by courts.