Republicans clash with Barack Obama over Syria refugee program

Washington: US lawmakers have moved to freeze White House plans to resettle Syrian refugees, intensifying a standoff with President Barack Obama who accused Republicans of "hysteria" following the Paris attacks.

Seizing upon fears one of the attackers may have entered Europe posing as a Syrian migrant, Republican leaders introduced legislation requiring assurances of more robust background checks and vetting before the White House can go ahead with its plan to welcome 10,000 refugees from the conflict in the coming year.

A vote on the measure, unveiled by House Homeland Security chairman Michael McCaul, could come today.

"It does put the brakes on the program until they can properly vet and certify that these individuals do not pose a threat to the national security of the United States," McCaul said.

The bill is aimed at strengthening vetting procedures for Syrian as well as Iraqi refugees in the wake of Friday's attacks that killed 129 people in Paris.

"I don't think we can afford to play Russian roulette with our national security," McCaul said.

Amid intensifying concern over extremists from the Islamic State group infiltrating the West, and as US lawmakers digest reports that several Paris attackers were French nationals, McCaul said lawmakers were also drafting legislation that would tighten the existing visa waiver program.

The program allows citizens of certain countries, including France and others in Europe, to travel to the United States without a visa.

"Obviously that's a vulnerability when you have 5,000 foreign fighters with Western passports. We need to tighten up those security gaps," McCaul said.

In an unusually fierce rebuke on the refugee issue, Obama struck out at Republicans, accusing them of demonising "widows and orphans."

"We are not well served when in response to a terrorist attack we descend into fear and panic," Obama said yesterday from Manila.

"We don't make good decisions if it's based on hysteria or an exaggeration of risks."

Congress is under extraordinary pressure to act after at least 27 US state governors voiced opposition to taking in further Syrian refugees.

McCaul's plan would require the director of the FBI, the Secretary of Homeland Security and the Director of National Intelligence to certify that each refugee is not a security threat.

"With that comes great liability," declared McCaul.