More than a dozen US state governors refused on Monday to accept Syrian refugees after the Paris attacks, part of a mounting Republican backlash against the Obama administration's plan to accept thousands more immigrants from the war-torn country.

Leading Republican presidential candidates called on President Barack Obama to suspend the plan to accept 10,000 Syrian refugees in the coming year and some Republican lawmakers began moves in Congress to try to de-fund the policy.

The State Department said the administration would stand by its plan, reiterating that the refugees would be subject to stringent security checks, and Obama said that the terrorism problem should not be equated with the refugee crisis.

Representational image. Source: Reuters

But Republican leaders said it was too risky to allow a further influx of refugees after Friday's attacks by the Syria-based Islamic State group that killed 129 people.

The Republican states rejecting further Syrian refugee settlements were South Carolina, Oklahoma, Idaho, Maine, Nebraska, Texas, Arkansas, Arizona, Indiana, Louisiana, Mississippi, Massachusetts, Ohio, North Carolina, Wisconsin, Georgia and Illinois.The governors of Alabama and Michigan had said on Sunday they would no longer help settle Syrian refugees.

One Democratic governor, Maggie Hassan of New Hampshire, joined them in rejecting Syrian refugees.

Here's a handy map on how the situation is across the states:

Experts in immigration law said the governors likely had no legal standing to block the federal government from settling refugees admitted into the country, but noted that they could obstruct the plans by cutting funding to programs and creating an atmosphere of hostility.

Louisiana Governor Bobby Jindal, for instance, said he had instructed law enforcement officials to monitor one Syrian refugee recently resettled into his state.

A Syrian passport found near the body of one of the attackers showed that its holder passed through Greece in October, raising concern that the attackers had entered Europe amid the wave of refugees fleeing that country's four-year civil war.

"Texas cannot participate in any program that will result in Syrian refugees - any one of whom could be connected to terrorism - being resettled in Texas," Texas Governor Greg Abbott said in an open letter to Obama on Monday. "Neither you nor any federal official can guarantee that Syrian refugees will not be part of any terroristic activity."

Refugee advocates argued that the governors and other Republicans are targeting those who are overwhelmingly victims rather than perpetrators of extremist violence.

"These are victims of the same terror that we're so horrified by," said Melanie Nezer, vice president of policy and advocacy at Jewish non-profit refugee service HIAS. "The impact on people is going to be tragic and the impact on our reputation as a global humanitarian leader is also going to be tragic."