Governors of multiple U.S. states said they will refuse Syrian refugees trying to settle in their states, after early investigations suggested that at least one of the Paris attackers may have been among the thousands of Syrians fleeing violence at home.

It was revealed on Saturday that a passport found at the scene of one of the attacks showed Syrian citizenship. According to Greek authorities, it was last registered in Greece at the beginning of October—a main stopover point in the passage from Syria to European countries. The document has not been directly linked to the attackers, though the suggestion lent a soft legitimacy to security concerns over incoming refugees.

The discovery re-ignited a conversation about providing safety for refugees while protecting citizens. On Monday morning, Govs. Greg Abbott (R) of Texas, Bobby Jindal (R) of Lousiana, Charlie Baker (R) of Massachusetts, Asa Hutchinson (R) of Arkansas, Mike Pence (R) of Indiana, and Bruce Rauner (R) of Illinois said they would not accept Syrian refugees.

Govs. Robert Bentley (R) of Alabama, and Rick Snyder (R) of Michigan both announced on Sunday that they would do the same, according to news reports.

It should be noted, though, that according to a report from ThinkProgress, these governors do not have constitutional authority to refuse refugees. "The problem for Jindal, Abbott and the other governors opposed to admitting refugees, however, is that there is no lawful means that permits a state government to dictate immigration policy to the president in this way," ThinkProgress explains.

Several Supreme Court cases along with the Refugee Act of 1980 grant the president the power to allow refugees into the United States. Despite this, many governors are speaking out.

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The Governors' statements.

Hutchinson Tweeted out his intentions on Monday morning:

"I—and millions of Americans—implore you to halt your plans to accept more Syrian refugees in the United States," Abbott wrote in a letter addressed to President Obama. "A Syrian 'refugee' appears to have been part of the Paris terror attack. American humanitarian compassion could be exploited to expose Americans to similar deadly danger. The reasons for such concerns are plentiful."

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"After full consideration of this weekend's attacks of terror on innocent citizens in Paris, I will oppose any attempt to relocate Syrian refugees to Alabama through the U.S. Refugee Admissions Program. As your Governor, I will not stand complicit to a policy that places the citizens of Alabama in harm's way," Bently said in a news release.

"Michigan is a welcoming state and we are proud of our rich history of immigration," Snyder said in a statement. "But our first priority is protecting the safety of our residents."

Gov. Jindal, who is also a GOP candidate for president tweeted out the following:

Massachusetts Gov. Baker told reporters on Monday that his state would not take in anymore refugees. “No, I’m not interested in accepting refugees from Syria,” Baker said. “I would need to know a lot more than I know now before I would agree to do anything.”

“My view on this is that the safety and security of the people of the Commonwealth of Massachusetts is my highest priority,” he continued.

Gov. Rauner issued the following statement:

“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. We must find a way to balance our tradition as a state welcoming of refugees while ensuring the safety and security of our citizens. Therefore, the state of Illinois will temporarily suspend accepting new Syrian refugees and consider all of our legal options pending a full review of our country’s acceptance and security processes by the U.S. Department of Homeland Security.”

Gov. Pence of Indiana issued this statement on Monday:

"In the wake of the horrific attacks in Paris, effective immediately, I am directing all state agencies to suspend the resettlement of additional Syrian refugees in the state of Indiana pending assurances from the federal government that proper security measures have been achieved. Indiana has a long tradition of opening our arms and homes to refugees from around the world but, as governor, my first responsibility is to ensure the safety and security of all Hoosiers. Unless and until the state of Indiana receives assurances that proper security measures are in place, this policy will remain in full force and effect."

Texas Governor Greg Abbot also released a statement on Twitter, saying "Security comes first."

The announcements come after a deadly series of attacks hit Paris Friday night, leaving 129 dead and hundreds more injured, and they mark a potent new stumbling block in the ongoing refugee crisis. The extremist group Islamic State, also known as ISIS or ISIL, claimed responsibility for the attacks Saturday morning, and France has since conducted airstrikes targeting the militants' stronghold.

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At least for some states, the announcements represented a shift in offers of aid to refugees. Michigan's Synder had been working with the federal government to establish a process for accepting refugees, the Detroit Free Press reports. "Isn't that part of being a good Michigander?" Snyder asked in September, stressing the importance of security screenings.

Responses from presidential candidates.

Many Republican presidential candidates, including Marco Rubio, Mike Huckabee, Ben Carson, Jeb Bush, and Ted Cruz have all said the U.S. should either tailor or halt its acceptance of Syrian refugees—some have even called for religious tests.

On Monday, Pres. Obama was in Turkey for a G-20 meeting where he said that Americans "do not have religious tests to our compassion."