The Obama administration warned states over the Syrian refugee crisis Wednesday, telling them in a letter they do not have legal authority to refuse the refugees, and states that do not comply may be subject to enforcement action.

The letter, from the Office of Refugee Resettlement (ORR), told state resettlement officials that they may not deny benefits and services to refugees based on their country of origin or religion.

“Accordingly, states may not categorically deny ORR-funded benefits and services to Syrian refugees,” the letter, dated Wednesday, says. “Any state with such a policy would not be in compliance with the State Plan requirements, applicable statutes, and their own assurances, and could be subject to enforcement action, including suspension and termination.”

The letter went on to say that the 1964 Civil Rights Act prohibits discrimination based on race and national origin in all programs that receive federal financial assistance.

“Thus, it is not permissible to deny federally funded benefits such as Medicaid or TANF to refugees who otherwise meet the eligibility requirements,” the letter says.

The letter came after more than two dozen governors, mostly Republicans, announced they would resist efforts to resettle Syrian refugees in their states in light of the November 13 terrorist attacks in Paris, and fears that ISIS militants could use the controversial program to infiltrate the U.S.

In the House, lawmakers overwhelmingly approved a bill last week improving screening for Iraqi and Syrian refugees. The bill requires comprehensive background checks of every refugee from Iraq or Syria before they can be admitted into the United States and certification that each does not pose a threat. The Obama administration says that the vetting process is already thorough and can take two years to complete.

The ORR reiterated the administration’s argument, saying that Syrian refugees are subject to even more precautions that other refugees, calling it “a multi-layered and intensive screening and vetting process involving multiple law enforcement, national security, and intelligence agencies across the Federal Government.”

“It is the most robust screening process for any category of individuals seeking admissions into the United States, and it is only after admission that ORR and our partners in resettlement begin our work,” the letter said.

Republicans reacted angrily to the letter, with House Judiciary Committee Chairman Bob Goodlatte calling the Obama administration’s stance “hypocritical."

“While the United States has the most generous refugee system in the world, the American people are rightly concerned about admitting Syrian refugees and the impact it would have on the safety of their families and neighbors,” Goodlatte, R-Va., said in a statement.

“In light of these concerns, the majority of state governors have taken positions that reflect the views of their residents. It’s hypocritical for Obama Administration officials to threaten enforcement action against these states when they refuse to enforce the vast majority of our immigration laws, such as cracking down on sanctuary cities that openly defy federal law and endanger the American people,” he said.

Roughly 2,200 Syrian refugees have been allowed in over the last four years. Obama has outlined a goal of bringing 10,000 more Syrian refugees to the U.S. during the current budget year.

The Associated Press contributed to this report.