COLUMBIA, Mo. — Missouri’s Republican governor and attorney general said in a letter to the U.S. Department of Justice on Thursday that they stand by the state’s new law that would ban police from enforcing federal gun rules.

Gov. Mike Parson and Attorney General Eric Schmitt wrote that they still plan to enforce the new law, which Parson signed Saturday. The measure would penalize Missouri police departments if their officers enforce federal gun laws.

Schmitt and Parson wrote that they will “fight tooth and nail” to defend the right to own guns as spelled out in the state constitution and the new law.

“We will not tolerate any attempts by the federal government to deprive Missourians of this critical civil right,” they wrote.

In a letter sent Wednesday night, Justice Department officials pointed out that federal law trumps state law under the U.S. Constitution’s Supremacy Clause.

Missouri’s law threatens to disrupt the working relationship between federal and local law enforcement agencies, wrote Brian Boynton, an acting assistant attorney general at the Justice Department. Boynton noted that the state receives federal grants and technical assistance.

Similar bills were introduced in more than a dozen other states this year, including Alabama, Arkansas, Nebraska, Oklahoma, South Carolina, Tennessee, Utah, Wyoming, New Hampshire, North Dakota, South Dakota, West Virginia and Iowa.

In Texas, people may now carry handguns without first getting a background check and training. This is the latest and largest on a growing list of states to roll back permitting requirements for carrying guns in public.

Republican Gov. Greg Abbott, who has called for the state to become a so-called Second Amendment sanctuary, held Thursday a ceremonial bill signing at the Alamo in San Antonio. He called it a measure of freedom and self-defense, while also connecting it to his ongoing fight with the Biden administration over the flow of migrants across the border with Mexico.

“There is a need for people to have a weapon to defend themselves in the Lone Star State,” Abbott said.

Gun-rights groups have made significant gains in efforts to relax gun possession laws. Several states have passed similar bills this year, including Tennessee, Utah and Iowa.

Montana and Wyoming also expanded the ability to carry without a permit. Legislation passed in Louisiana but is expected to be vetoed. Republican-controlled legislatures in Pennsylvania and Ohio also are considering similar bills.

The Texas law takes effect Sept. 1 and Abbott signed the bill over the objections of law enforcement groups who say the change will endanger the public and police. The law backed by gun-rights groups including the National Rifle Association, who argue it will allow Texans to better defend themselves and remove hurdles to the constitutional right to bear arms.

The NRA has called it the “most significant” gun-rights measure in the state’s history.

“In this increasingly dangerous world, people want to be able to protect themselves,” said NRA leader Wayne LaPierre, who attended the Texas bill signing. “Thank God Texas is leading the way for the country in making that possible.”

Gun-control groups also oppose the Texas measure, noting the state’s recent history of mass shootings, including a racist attack at a Walmart in the border city of El Paso, and attacks at a Baptist church in Sutherland Springs and at Santa Fe High School outside Houston.

“This is about creating a profitable culture of fear and do-it-yourself armed security, and there is no evidence that these laws promote public safety,” Ari Freilich, state policy director for the Giffords gun-control advocacy group, said in a statement.