BBC News, Washington

A federal judge has temporarily blocked the Trump administration’s attempt to deport Palestinian activist Mahmoud Khalil, who was arrested over the weekend by immigration agents.
Mr Khalil, a Columbia University graduate and permanent US resident, played a key role in last year’s Gaza war protests at the Ivy League campus in New York City.
The arrest is part of President Donald Trump’s pledge to crackdown on pro-Palestinian protesters on college campuses, in what he called “the first arrest of many to come”.
Protesters gathered in New York City on Monday afternoon pushing for Mr Khalil’s release and condemning the Trump administration’s actions.
A crowd waving Palestinian flags gathered in Lower Manhattan’s Foley Square soon after it was reported that the US had attempted to deport Khalil. The protesters later marched further south toward city hall. At least one person was detained.
“We’re facing a horrifying reality that our own student, a member of the Columbia community, has become a political prisoner here in the United States,” Columbia University Professor Michael Thaddeus said in a statement.
The judge set a hearing for Wednesday where Mr Khalil is expected to make an appearance, according to court documents.
Immigration and Customs Enforcement (ICE) agents informed Mr Khalil they were revoking his student visa and green card upon taking him into custody on Saturday, his lawyer said.
The Department of Homeland Security (DHS) accused the former student of “leading activities aligned to Hamas” but provided no details. The BBC has asked the agency for further information on the allegations.
Trump has previously stated that foreign students found to be “terrorist sympathisers” would face deportation. Mr Khalil is the first known detainee under this policy.
His lawyer, Amy Greer, condemned his detention as “terrible and inexcusable”, calling it part of “the US government’s open repression of student activism and political speech”.
Mr Khalil, a Palestinian refugee who was born in Syria, has not been charged with any crime.
ICE agents detained him at his university-owned Manhattan apartment and initially placed him in a New Jersey immigration facility before transferring him to a detention centre in Jena, Louisiana, according to ICE records.
His attorney claims ICE also threatened to arrest his wife, an American citizen who is eight months pregnant. When she attempted to visit him in New Jersey, officials told her he was not there.
Columbia University stated that law enforcement can enter campus property with a warrant but denied that university leadership had invited ICE agents.
On Sunday, Secretary of State Marco Rubio reaffirmed the administration’s stance, posting on X: “We will be revoking the visas and/or green cards of Hamas supporters in America so they can be deported.”
The Trump administration announced last week it was rescinding $400m (£310m) in federal grants to Columbia, accusing it of failing to fight antisemitism on campus.
Columbia was the epicentre last year of pro-Palestinian student protests nationwide against the war in Gaza and US support for Israel.
Mr Khalil was lead negotiator for Columbia University Apartheid Divest when its protesters set up a huge tent encampment on the university lawn in protest against the Gaza war.
He later told the BBC he had been temporarily suspended by the university, where he was a graduate student at the School of International and Public Affairs.
New York Civil Liberties Union President Donna Lieberman called his deportation “targeted retaliation and an extreme attack on the First Amendment.”
New York Attorney General Letitia James said she was “extremely concerned” and monitoring the case.

Some Jewish students at Columbia claim that protest rhetoric sometimes crossed the line into antisemitism, while others have joined the the pro-Palestinian demonstrations.
Carly, a Jewish-American graduate student at Columbia and a friend of Mr Khalil, told the BBC that the detainee was a “very, very caring soul”.
“He has been very targeted online and just seeing how he has been so misrepresented, it’s very painful, as someone who knows him on a personal level,” said Carly, who declined to share her surname for privacy reasons.
Speaking on Fox News, Trump’s border tsar Tom Homan alleged that Mr Khalil had violated the terms of his visa by “locking down buildings and destroying property”.
The Israeli military launched its campaign against Hamas in response to an unprecedented cross-border attack into Israel on 7 October 2023, which left about 1,200 people dead and 251 taken hostage.
More than 48,000 Palestinians in Gaza have been killed in Israel’s military action, according to the Hamas-run health ministry.
With additional reporting from Nada Tawfik