Topeka ? A national gun control group is arguing in a lawsuit that a Kansas law challenging federal authority to regulate guns is unconstitutional and endangers public safety.

The Washington-based Brady Campaign to Prevent Gun Violence filed the lawsuit Wednesday against a 2013 law declaring that the federal government has no authority to regulate guns manufactured, sold and kept only in Kansas.

The law also makes it a felony for any U.S. government employee to attempt to enforce federal regulations for Kansas-only firearms, ammunition or accessories.

The lawsuit says gun regulations fall under the power of Congress to regulate interstate commerce and the state is improperly trying to nullify federal law. It says the effects of not regulating some guns could be far-reaching.

Gov. Sam Brownback has promised to defend the law.