President Donald Trump has signed an executive order suspending the US refugee programme for 120 days, specifically barring Syrian refugees until further notice.
Trump signed the order at the Pentagon, saying the moves would help protect Americans from "terrorist" attacks.
"I'm establishing new vetting measures to keep radical Islamic terrorists out of the United States of America. Don't want them here," Trump said earlier on Friday.
"We only want to admit those into our country who will support our country and love deeply our people," he said.
France and Germany are "concerned" over Trump's move to restrict refugee arrivals, French Foreign Minister Jean-Marc Ayrault said.
"This decision can only cause us concern," he said following a meeting with his German counterpart Sigmar Gabriel. "Welcoming refugees who are fleeing war is part of our duty."
Meanwhile, a spokesman for Czech President Milos Zeman praised Trump's steps.
"Trump protects his country, he's concerned with the safety of his citizens. Exactly what EU elites do not do," Zeman's spokesman Jiri Ovcacek said in a tweet.
Civil rights groups condemned the measures as discriminatory.
"Trump's latest executive order is likely to hurt the people most in need: those fleeing violence and terrorism - and on Holocaust Remembrance Day, no less," said Grace Meng, senior US researcher at Human Rights Watch.
"The decision to drastically curtail the refugee programme will abandon tens of thousands to the risk of persecution or worse and cede American leadership on a vitally important issue," Meng added.
The order suspends the Syrian refugee programme until further notice, and will eventually give priority to minority religious groups fleeing persecution. Trump said in an interview with a Christian news outlet the exception would help Syrian Christians fleeing the civil war.
His order had been expected to include a directive about setting up "safe zones" for Syrian refugees inside the country, but no such language was included.
The measure limits entry for at least 90 days from Syria and other Muslim-majority countries, but did not list the countries by name.
The state department said the three-month ban in the directive applied to Iraq, Syria, Iran, Sudan, Libya, Somalia and Yemen - all Muslim-majority nations.
Al Jazeera's Dorsa Jabbari, reporting from Tehran, said: "[Iranians] are shocked and astonished that this has taken place. There's more than one million Iranians living in the US. A lot of them have extended family, or their children, or their parents still in Iran."
Ardeshir Namavar, a US green card holder currently in Tehran, told Al Jazeera: "We feel really terrible about the news. I bought my ticket [to the US] and have a flight in 10 days; now we don't know what we are going to do. All of my family are in the US including my mother and father. They are American citizens. I had planned to study there, now everything has changed."
The order said all immigration programmes should include questions to "evaluate the applicant's likelihood of becoming a positively contributing member of society".
Jennifer Sime, the senior vice president of US programmes at the International Rescue Committee, an NGO that works with refugees, told Al Jazeera: "I think it's important to understand that there is already a robust vetting process in place. It was reviewed a few days ago and new things were added to enhance the vetting process."
She added that refugees were already the "single most vetted population coming into the US".
On the exception in the order that favours Syrian Christian refugees, Sime said: "The first thing to remember is that this programme [was] based on the principle of non-discrimination, so it's not about choosing Muslims or Christians. Refugees are selected based on need, urgency and basically their cases, not based on political affiliation and religion."
Trump's order cuts the number of refugees the US plans to accept this budget year by more than half, to 50,000 people from around the world.
During the last budget year, the US accepted 84,995 refugees, including 12,587 people from Syria. President Barack Obama had set the current refugee limit at 110,000.
During the Obama administration, vetting for refugees included in-person interviews overseas, where they provided biographical details about themselves, including their families, friendships, social or political activities, employment, phone numbers, email accounts and more.
They also provided biometric information, including fingerprints. Syrians were subject to additional, classified controls that administration officials at the time declined to describe, and processing for that group could routinely take years to complete.
Following Trump's signing of the order, the Council on American-Islamic Relations (CAIR), a US Muslim advocacy and civil rights group, said it would file a "federal lawsuit on behalf of more than 20 individuals challenging the 'Muslim ban'".
Source: Al Jazeera and news agencies