Trump's executive order bars citizens of seven Muslim-majority countries from entering the United States for the next 90 days and suspends the admission of all refugees for 120 days.
Here are the latest developments of a day filled with airport detentions, protests and legal maneuvering:
• Two Iraqis who were named as the petitioners in the motion had been released by Saturday night, but lawyers said in a court filing that "dozens and dozens" of people remained in detention at JFK.
• Protesters converged on at least eight major US airports
, demonstrating against the policy, which critics see as a Muslim ban, and other White House actions. Protests are scheduled Sunday in Orlando, Boston, Philadelphia, Atlanta, Seattle, Washington and Chicago, mostly at airports.
• A Trump official who was briefing reporters cited the attack that killed 14 people in San Bernardino as an example of the immigration connection to terror attacks in the United States. But neither of the shooters would have been affected
by the new ban.
• President Trump said the government was "totally prepared" for the ban. "It's working out very nicely," Trump told reporters Saturday. "You see it at the airports. You see it all over. It's working out very nicely and we're going to have a very, very strict ban." However. there was widespread confusion
across the country as authorities at airports struggled to adjust to the new directives.
Judge rules people can stay
Travelers who fit the ban's criteria and were already in the air headed for the United States on Friday afternoon when Trump signed the executive order were stopped and detained upon arrival at US airports. Others with valid visas and airline tickets were prevented from boarding planes destined for the United States -- some stranded in foreign countries -- as airlines and foreign airport officials scrambled to understand and comply with the new US immigration policy.
But Saturday night, a federal judge granted an emergency stay for people who have already arrived in the United States and those who are in transit, and who hold valid visas, ruling they cannot be deported. However, it doesn't immediately order that they be released from detention, Zachary Manfredi, a lawyer involved in drafting the motion, told CNN.
Judge Ann Donnelly, who was appointed by former President Barack Obama, wrote in her decision that government could not remove "individuals with refugee applications approved by US Citizenship and Immigration Services as part of the US Refugee Admissions Program, holders of valid immigrant and non-immigrant visas, and other individuals from Iraq, Syria, Iran, Sudan, Libya, Somalia and Yemen legally authorized to enter the United States."
Anthony D. Romero, the director of the American Civil Liberties Union, said the judge recognized the potential of harm to immigrants and visitors.
"Our courts today worked as they should as bulwarks against government abuse or unconstitutional policies and orders," he said.
A senior official at the Department of Homeland Security told reporters on a conference call they had not yet seen the ruling.
"We will be analyzing it with our counsel and we will certainly implement any appropriate orders accordingly," the official said.
Trump: 'We don't want them here'
The executive order was quickly decried as a "Muslim ban" by Democrats, human rights organizations and advocacy groups, who slammed Trump for instituting a policy they say cuts against US values and America's image around the world as a sanctuary for those fleeing oppression.
Trump rejected the criticism, insisting Saturday that the new policy did not amount to "a Muslim ban" like the one he called for in December 2015 in the heat of the Republican primary campaign.
Trump's actions on Friday, though, were consistent with his pledge during the campaign to stop immigration from many Muslim-majority countries, particularly those he loosely defined as historically prone to terrorism.
At John F. Kennedy International Airport, where passengers can often spot the Statue of Liberty on their descent into New York, a dozen travelers who fit the ban's criteria were detained and prevented from exiting the airport. Protesters and a handful of Democratic congressmen soon arrived to demand their release.
Former Secretary of State and Democratic presidential nominee Hillary Clinton weighed in Saturday night, tweeting, "I stand with the people gathered across the country tonight defending our values & our Constitution. This is not who we are."
Among the group of people detained Saturday were two Iraqis traveling on special immigrant visas. Hameed Khalid Darweesh and Haider Sameer Abdulkaleq Alshawi were later released.
At least 10 other people were in custody throughout the day.
A senior DHS official told reporters that the United States denied entry to 109 travelers who were in transit to the country at the time the executive order was signed. The travelers were from Iran, Iraq, Sudan, Syria, Somalia, Libya or Yemen, and were traveling on non-immigrant visas.
The official could not say how many had left the United States already and how many were still being detained. In addition, 173 were told not to board aircraft to the United States.
Trump on Friday said that his actions would "keep radical Islamic terrorists out of the United States of America."
"We don't want them here," Trump said as he signed the order.
But those actions also hit green card holders, lawful permanent US residents, with heavy impact, two sources familiar with the matter told CNN. Those travelers also fell under the ban's heavy curtain, though they could apply for a waiver to enter the United States after traveling abroad.
But the senior DHS official told CNN that no green card holders were denied entry
At the Cairo International Airport, Egyptian officials on Saturday began to turn back US-bound refugees and citizens of the seven countries now barred from entering the United States.
"This is a new era we are witnessing," a Cairo airport official said.
Airlines, meanwhile, scrambled to understand the new US policy and worked to warn passengers who might be affected before they boarded their flights.
Trump administration officials responded to the wide-ranging criticism, saying the United States had to take these actions so it can reform its vetting procedures and that it was built out carefully over the past few weeks during the transition.
Iran, one of the countries whose citizens were banned, slammed Trump's immigration order on Saturday as an "insult" and a "gift to extremists" and said it was considering its response.
Iran will take "proportionate legal, consular and political action and ... will take reciprocal measures in order to safeguard the rights of its citizens until the time of the removal of the insulting restrictions of the government of the United States against Iranian nationals." Iran's foreign ministry said in a statement Saturday.
The disarray also fell against a backdrop of swift condemnation from human rights groups and national security experts.
The International Rescue Committee, a humanitarian aid and refugee assistance group, called Trump's decision to suspend refugee admissions "harmful and hasty" and noted that the US refugee program "makes it harder to get to the United States as a refugee than any other route." Refugees must undergo an extensive vetting process -- it typically takes more than two years to be admitted to the United States as a refugee.
"In truth, refugees are fleeing terror -- they are not terrorists," David Miliband, the group's president and chief executive, said in a statement. "And at a time when there are more refugees than ever, America must remain true to its core values. America must remain a beacon of hope."
Correction: The combined population of the seven countries named in the executive order -- Iran, Iraq, Libya, Somalia, Sudan, Syria and Yemen -- is roughly 218 million, according to 2015 data published by the World Bank. An earlier version of this story incorrectly used a lower figure.