29 January 2017 08:54 am Views - 8539
The American Civil Liberties Union (ACLU) filed a lawsuit early on Saturday in response to the order.
The judge's stay prevents those "caught up" in the aftermath from being deported, the ACLU said.
The group estimates that between 100 and 200 people are being detained at airports or in transit.
The court decision came as hundreds protested at airports in several US states over Donald Trump's clamp down on immigration.
The ruling, from Judge Ann Donnelly, prevented the removal from the US of people with approved refugee applications, valid visas, and "other individuals... legally authorised to enter the United States".
Lee Gelernt, deputy legal director of the Immigrants Rights Project, argued the case in court and was greeted by a cheering crowd outside.
He said that some people had been threatened with being "put back on a plane" later on Saturday.
"The judge, in a nutshell, saw through what the government was doing and gave us what we wanted, which was to block the Trump order and not allow the government to remove anybody who has come and is caught up in the order, nationwide," he told the crowd.
He also said the judge had ordered the government to provide a list of names of those detained under the order.
"We are going to see each of the people, provide counsel, try and get them out of detention right now - but at minimum, they will not be returned back to danger," Mr Gelernt said.
The court has set a date to hear the case for the end of February.
"This is a remarkable day," said the ACLU's executive director, Anthony Romero.
"On day one after he signed the executive order, we took him to court… that it was unconstitutional, that it was un-American, and that it flew in the face of established statutes that we have long regarded in this country."
"What we've shown today is that the courts can work... they're a bulwark in our democracy, and when President Trump enacts laws or executive orders that are unconstitutional and illegal, the courts are there to protect everyone's rights."(BBC)