NEWY YORK, United States (AFP) — Mahmoud Khalil, one of the most prominent leaders of United States (US) pro-Palestinian campus protests, sued the Trump administration Thursday for US$20 million over his arrest and detention by immigration agents.

Khalil, a legal permanent resident in the United States who is married to a US citizen and has a US-born son, had been in custody following his arrest in March.

The 30-year-old was freed from a federal immigration detention center in Louisiana last month, hours after a judge ordered his release on bail.

“The administration carried out its illegal plan to arrest, detain, and deport Mr Khalil ‘in a manner calculated to terrorise him and his family,’ the claim says,” according to the Center for Constitutional Rights which is backing Khalil.

Khalil suffered “severe emotional distress, economic hardship (and) damage to his reputation,” the claim adds.

The Columbia University graduate was a figurehead of student protests against US ally Israel’s war in Gaza, and the Trump administration labeled him a national security threat.

Khalil called the lawsuit a “first step towards accountability.”

“Nothing can restore the 104 days stolen from me. The trauma, the separation from my wife, the birth of my first child that I was forced to miss,” he said in the statement.

“There must be accountability for political retaliation and abuse of power.”

Khalil has previously shared his “horrendous” experience in detention, where he “shared a dorm with over 70 men, absolutely no privacy, lights on all the time.”

Assistant Department of Homeland Security Secretary Tricia McLaughlin said “the Trump Administration acted well within its statutory and constitutional authority to detain Khalil, as it does with any alien who advocates for violence, glorifies and supports terrorists, harasses Jews, and damages property.”

President Donald Trump’s government has justified pushing for Khalil’s deportation by saying his continued presence in the United States could carry “potentially serious adverse foreign policy consequences.”

Khalil’s detention came amid Trump’s campaign against top US universities in recent months, with the president facing off against Columbia, Harvard and other schools over foreign student enrollment while cutting federal grants and threatening to strip accreditation.

Beyond his legal case, Khalil’s team has expressed fear he could face threats out of detention.