Washington: The deadly Paris attacks have intensified Republican opposition to letting thousands of Syrian refugees come to the United States.
Republican presidential contender Marco Rubio on Sunday said the United States cannot do so because it's impossible to know whether people fleeing Syria have links to Islamic militants an apparent shift from earlier statements in which he left open the prospect of migrants being admitted with proper vetting.
"It's not that we don't want to, it's that we can't," Rubio said Sunday on ABC's "This Week." "Because there's no way to background check someone that's coming from Syria. Who do you call and do a background check on them?"
The question of admitting Syrian refugees has for months been part of the national security discussion among 2016 candidates that cuts to the heart of the American identity as a refuge.
Former Florida Gov. Jeb Bush on Sunday told NBC's "Meet the Press" that the US should admit Syrian Christians, after proper vetting. Other Republican candidates have called for a ban on allowing Syrians into the US.
All three Democratic presidential candidates have said they would admit Syrians but only after thorough background checks.
But Friday night's mass killings in Paris, which left at least 129 people dead, offered evidence that may have backed up what many, including Rubio, had been warning: People with secret ties to Islamic militants could flow across borders as part of waves of refugees.
Authorities said a Syrian passport found near one of the Paris attackers that had been registered last month and traveled through three countries along a busy migrant corridor known for lax controls. It was not clear whether the document was real or forged.
Officials on Sunday were still trying to identify people involved in the conspiracy. They said as many as three of the seven suicide bombers who died in the attacks were French citizens.
Republican presidential contender Ben Carson, a retired brain surgeon, said that from the viewpoint of the Islamic State group, it would be "almost malpractice" not to do everything possible to infiltrate the refugee ranks with militants bent on waging jihad.
A spokesman for President Barack Obama said Sunday that the administration is moving forward with its plan to thoroughly vet and admit as many as 10,000 Syrian refugees.