TOPEKA, Kan. (AP) — A national gun control group is preparing to release the details of its legal challenge against a Kansas law declaring that the federal government has no authority to regulate guns manufactured, sold and kept only in the state.

The Washington-based Brady Center to Prevent Gun Violence had promised it would file a federal lawsuit Wednesday against the state law.

The Kansas law was enacted in 2013 and makes it a felony for any U.S. government employee to attempt to enforce a federal regulation or treaty when it comes to Kansas-only firearms, ammunition or accessories.

A similar law enacted in 2009 in Montana was struck down by the federal courts.

Kansas Gov. Sam Brownback is promising a vigorous defense of his state’s law.