A federal judge has blocked part of President Donald Trump's executive order on immigration, ruling that travellers who have already landed in the US with valid visas should not be sent back to their home countries.
Lawyers had filed a legal case in response to the order that includes a 90-day entry ban on citizens of seven Muslim-majority nations.
US District Judge Ann Donnelly's ruling late on Saturday concerns dozens of people who were detained at US airports following Trump's actions.
The American Civil Liberties Union (ACLU), which had filed a class action lawsuit against the ban, hailed the temporary stay of execution as a victory.
"This ruling preserves the status quo and ensures that people who have been granted permission to be in this country are not illegally removed off US soil," Lee Gelernt, deputy director of the ACLU's Immigrants' Rights Project, said.
ACLU said it would help 100 to 200 people with valid visas or refugee status, who found themselves detained in transit or at US airports after Trump signed the order late on Friday.
The legal case was raised after two Iraqis were held by law enforcement officials at John F Kennedy International Airport (JFK) while trying to legally enter the country.
More than 100 detained
At least 12 travellers have been detained at JFK, prompting mass protests at the airport.
Less than 24 hours into the ban, Homeland Security said that at least 109 travellers had been denied entry into the US in total.
Homeland Security said on Sunday it would "comply with judicial orders", referring to Donnelly's ruling, but that Trump's order remains in place.
A group of state attorneys general, meanwhile, are discussing whether to file their own court challenge against the order, officials in three states told the Reuters news agency.
Officials in the offices of attorneys general in Pennsylvania, Washington and Hawaii said they were evaluating what specific claims could be filed, and in which court.
Trump signed the executive order on Friday that effectively denies entry to refugees from seven Muslim-majority countries, including those with green cards, who otherwise have permanent residence in the US.
Signing the order at the Pentagon, Trump said the move would help protect Americans from "terrorist" attacks.