Rubio’s letter notified DHS that he had revoked both targets’ visas, setting in motion plans for U.S. Immigration and Customs Enforcement to arrest and attempt to deport them, according to a senior DHS official and another U.S. official who spoke on condition of anonymity to describe how the operation against Khalil took shape.

Trying to deport Khalil for demonstrating against Israel is an obvious violation of his rights and an attempt to intimidate others, they say.

Lawyers for Mahmoud Khalil, a Columbia graduate and legal resident from Syria, are asking a federal judge to order U.S. immigration authorities to immediately release him and find his detention in violation of the First Amendment.

A DHS official defended Khalil’s detention in an interview on Thursday but did not provide additional details for his arrest.

Khalil's case could set a precedent for how the US handles similar situations in the future, with significant implications for free speech and immigration policy - Anadolu Ajansı

Some protesters held signs that read "Fight Nazis not students," "Free Mahmoud free Palestine" and "You can’t deport a movement."

Nearly 100 people were arrested after protesters gathered at Trump Tower in Manhattan Thursday to denounce the arrest of Mahmoud Khalil, a Palestinian activist detained by ICE over his involvement with pro-Palestinian demonstrations at Columbia University.

I was a student at Columbia University, where I covered tense campus protests over the Israel-Hamas war for the college newspaper and for POLITICO. So I’m familiar with Mahmoud Khalil, a former Columbia student who I’ve chatted with in the past and appears to be the first target of the Trump administration’s effort to crack down on student protesters.

Noor Abdalla, wife of detained Palestinian Columbia University student Mahmoud Khalil, says she thought her husband didn't have to worry about ICE.