Authorities in Vermont on Monday arrested a Palestine protest organiser after he arrived at an immigration office to complete a final step towards becoming a US citizen.

Mohsen Mahdawi, a green card holder who has lived in the US since 2014, had walked into the federal office for an interview but was instead arrested by plain-clothed agents.

“These individuals refused to provide any information as to where he was being taken or what would happen to him,” Vermont senators Bernie Sanders and Peter Welch said in a statement, along with Vermont Representative Becca Balint.

“This is immoral, inhumane and illegal. Mr Mahdawi, a legal resident of the United States, must be afforded due process under the law and immediately released from prison.”

One of Mr Mahdawi's lawyers, Andy Delaney, told The National that he had never seen anything like this happen before.

“This is atypical,” he said. “I’ve seen [immigration authorities] show up when people are charged with crimes and they show up to court and detain someone … but this was supposed to be a naturalisation interview.”

Mr Delaney and other lawyers filed a petition in federal court seeking an order barring the government from removing Mr Mahdawi from the state or country. Mr Delaney said his client was being held in the Vermont city of St Albans and a judge had issued a temporary restraining order blocking his transfer.

According to the court filing, Mr Mahdawi was born in a refugee camp in the West Bank and moved to the US in 2014. He recently completed coursework at Columbia and was expected to graduate in May before beginning a master's degree programme there in the autumn.

“Prior to and following Mr Mahdawi’s detention, the government has made clear that it intends to retaliate and punish individuals such as Mr Mahdawi who advocated for ceasefire and ending the bloodshed in Gaza,” the filing states.

The arrest “plainly violate[s] the First Amendment, which protects Mr Mahdawi’s right to speak on matters of public concern and prevents the government from chilling constitutionally protected speech".

The habeas corpus petition describes Mr Mahdawi as a committed Buddhist who believes in “non-violence and empathy as a central tenet of his religion.”

In January, President Donald Trump signed an executive order that called for the revocation of visas of foreign students and others who took part in pro-Palestinian protests on university campuses.

As a student, Mr Mahdawi was an outspoken critic of Israel's military campaign in Gaza and organised campus protests until March 2024. He co-founded the Palestinian Student Union at Columbia with Mahmoud Khalil, another Palestinian permanent resident of the US and graduate student who was recently detained by the Immigration and Customs Enforcement agency.

Christopher Helali, a friend of Mr Mahdawi who lives near him in Vermont, was outside the immigration office when Mr Mahdawi was detained and recorded a video of him being led away by authorities. In the video, which Mr Helali posted on X, Mr Mahdawi is shown giving a peace sign with his hands and being led away to a car.