US President Barack Obama on Wednesday slammed domestic "hysteria" over the security risks posed by Syrian refugees.

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

Obama then accused his political foes of fearing "widows and orphans," saying "apparently they are scared of widows and orphans coming into the United States of America."

This comes after White House officials "briefed the governors on the rigorous screening and security vetting process" for 90 minutes, urging 34 state governors not to implement measures that would block Middle Eastern refugees.

The governors of Michigan, Pennsylvania, Vermont and other states participated in the discussions, with Rick Snyder, Republican Governor of Michigan, saying he'd like "more robust data" on the refugee system.

Peter Shumlin, Democratic Governor of Vermont, told White House officials that he has faith in the "rigorous" screening process, and reiterated to the other governors that terrorists win "when we give into fear."

Senator Ben Cardin, the lead Democrat on the Foreign Relations Committee, said Washington should look at the strongest possible selection process to ensure "terrorists cannot get into the United States through our refugee program."

He added that the current US screening process takes 18 to 24 months, and is tighter than in Europe.

Republican governors call for a "pause"

This comes after more than 20 Republican lawmakers in Congress called on Obama's administration to "pause" its Syrian refugee resettlement system.

US House Speaker Paul Ryan, who was voted in as House speaker less than three weeks ago, told reporters in Washington, "The prudent, the responsible thing is to take a pause in this particular aspect of this refugee program in order to verify that terrorists are not trying to infiltrate the refugee population."

Republican presidential hopefuls also called for stronger vetting procedures, with Texas Senator Ted Cruz proposing that the refugees take a religious test.

Meanwhile, Secretary of State John Kerry defended the US' refugee resettlement program. He said in an interview with American broadcaster NBC that out of 785,000 refugees that have been accepted since 2001, only 12 "were found to perhaps be problematic with respect to potential terror."

Canada also worried

Prime Minister Justin Trudeau's plan for Canada to take in more than 25,000 Syrian refugees by year's end appears to be going full-steam.

However, the drive could divide the nation, as online petitions gathered show 45,000 for fast-tracking refugee claims and 70,000 against.

Since being sworn in two weeks ago, Trudeau has mobilized several government ministries to get the job done.

He told reporters, while in the Philippines for the Asia-Pacific Economic Cooperation (APEC), that his government "will make every effort" to resettle the asylum seekers.

Brad Wall, the Premier of Saskatchewan, urged Trudeau in an open letter that: "If even a small number of individuals are able to enter Canada as a result of a rushed refugee resettlement process, the results could be devastating."

Other premiers have also expressed doubt over the refugee plan.

smm/bw (AFP, AP, Reuters)