COLUMBIA, Mo. (AP) — Missouri Gov. Jay Nixon says it’s up to the federal government to screen refugees and is calling for safeguards following deadly terror attacks in Paris.

But the Democrat in a statement Monday didn’t say he’d block Syrian refugees from settling in Missouri.

Republican gubernatorial candidates suburban St. Louis businessman John Brunner, former state House speaker and U.S. attorney Catherine Hanaway and Lt. Gov. Peter Kinder want Nixon to do so. They cited safety concerns. Eighteen Republican state senators similarly called to suspend Syrian refugee relocation. The U.S. State Department’s Refugee Processing Center says 29 Syrian refugees settled in Missouri from Jan. 1 through Monday.

The president and CEO of the U.S Committee for Refugees and Immigration says under the Refugee Act of 1980 governors cannot legally block refugees.

That’s not stopping Kansas Gov. Sam Brownback from trying. Gov. Brownback has issued an executive order forbidding any state agencies or organizations that receive state grant money from helping relocate Syrian refugees in his state. Brownback said Monday the action was necessary because the federal government can’t guarantee Syrian refugees coming to America aren’t terrorists. He says refugees fleeing persecution in their own country might be better served by resettling in a friendly country closer to their homes.

Brownback acknowledged that many people seeking refugee status are peaceful and looking for a better life, but said Kansas can’t allow an influx of Syrian refugees while the Islamic State group is threatening to infiltrate the refugee process. Lt. Gov. Jeff Colyer says the well-being of Kansans is a higher priority than helping refugees.

Iowa Gov. Terry Branstad says Syrian refugees shouldn’t be resettled in Iowa until there is a federal review to ensure safety. Branstad late Monday said he had ordered state agencies to halt any future work on Syrian refugee resettlements in light of the terrorist attacks in Paris. Earlier in the day, he expressed concerns about safety, but said he may not have the authority to block Syrian refugees from entering the state. Several U.S. governors said they will halt efforts to allow Syrian refugees into their states. The governors are responding to heightened concerns that terrorists might use the refugees as cover to sneak across borders.

Branstad said intelligence agencies should review the security process. According to the State Department’s refugee processing center, no Syrian refugees have been resettled in Iowa.

Nebraska Gov. Pete Ricketts says he does not want Syrian refugees resettling in Nebraska until the federal government conducts a full review of its screening procedures to ensure public safety. Ricketts sent a letter Monday to refugee resettlement agencies in the state, urging them not to pursue resettlement of the refugees in light of the terrorist attacks in Paris. Ricketts says in the letter that while he understands the danger and persecution many are facing in the Middle East, it’s important to focus first on the safety of Nebraska residents and Americans. Ricketts says he’s been told no Syrian refugees have been resettled in Nebraska.