The refugee assistance program is administered by a variety of federal agencies, including the State Department and Homeland Security, according to the American Immigration Council.
After a refugee has been conditionally accepted for resettlement, the Refugee Processing Center works with private voluntary agencies to determine where the refugee will live in the United States.
Individual states may provide services, but have no responsibility for placement, which often falls to local churches and charities.
Wisconsin Gov. Scott Walker said his first responsibility was to protect the state's citizens. "Along with governors across the country, I have deep concerns about the Obama administration's plan to accept 10,000 or more Syrian refugees, especially given that one of the Paris attackers was reportedly a Syrian refugee," Walker said in a prepared statement. "In consultation with our Adjutant General, who also serves as my Homeland Security Advisor, it is clear that the influx of Syrian refugees poses a threat."
Walker called on Obama to immediately suspend the program pending a full review of its security and acceptance procedures.
But in a letter to Secretary of State John Kerry and Secretary of Health and Human Services Sylvia Burwell, Walker said he directed Secretary Eloise Anderson of the Wisconsin Department of Children and Families to not participate in the resettlement of Syrian refugees in Wisconsin.
" Our state will not facilitate the coordination or provision of benefits or services for individuals whose presence could pose a potential risk to our people," Walker wrote in the letter. "We will make all efforts to ensure that Syrian refugees are not resettled within the boundaries of our state."
Walker did not spell out what those efforts might be.
Illinois Gov. Bruce Rauner also announced Monday the state is putting a hold on accepting any new refugees from Syria.
"Our nation and our state have a shared history of providing safe haven for those displaced by conflict, but the news surrounding the Paris terror attacks reminds us of the all-too-real security threats facing America," the governor said in prepared statement.
As for a federal response, House Speaker Paul Ryan, R-Janesville, called Tuesday for a "pause" in the Syrian refugee program in the U.S. until there are guarantees it can't be infiltrated by terrorists.
"This is a moment when it's better to be safe than to be sorry. So we think 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," Ryan said at a news conference after a closed-door meeting of House Republicans.
Ryan said Republicans in the House will be preparing a legislative response to the Syrian refugee crisis in the wake of the Paris attacks, and details of those bills will be announced later.
President Obama, however, made no indication that he would be pursing any refugee restrictions.
"The people who are fleeing Syria are the most harmed by terrorism," Obama said in Antalya, Turkey, at a meeting of the G20. "It is very important ... that we do not close our hearts to these victims of such violence and somehow start equating the issue of refugees with the issue of terrorism."