(AP) — A federal judge is allowing two gun-rights groups to proceed with their legal challenge against a Nebraska law that only lets U.S. citizens obtain concealed-carry permits.

U.S. District Judge Richard Kopf ruled that the case can move forward on arguments that the law violates equal-protection rights, and may be pre-empted by federal law.

The lawsuit was filed on behalf of Carlos Nino De Rivera Lajous, a Mexican man who has been legally living in Lincoln since 1990. Wesley Dickinson, president of the Nebraska Firearms Owners Association, says the ruling moves the state one step closer to letting legal immigrants qualify for permits to carry concealed weapons.

Kopf rejected arguments that the violated the constitutional right to bear arms.