President Donald Trump on Friday put a four-month hold on allowing refugees into the United States and temporarily barred visitors from Syria and some other Muslim-majority countries, saying the moves would help protect Americans from terrorist attacks.
Civil rights groups condemned the measures as discriminatory.
"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 at the Pentagon.
"We only want to admit those into our country who will support our country and love deeply our people," he said.
The order suspends the Syrian refugee program 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 there.
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.