SEATTLE (AP) — A judge has upheld Seattle's so-called "gun violence tax" in a challenge brought by gun rights groups.

King County Superior Court Judge Palmer Robinson on Tuesday rejected arguments from the National Rifle Association and others that Washington state prohibits local governments from adopting laws related to firearms unless those laws are specifically authorized by the Legislature.

Seattle adopted the tax over the summer, modeling it on one in Cook County, Illinois. It calls for adding $25 to the price of each firearm sold in the city, plus 2 or 5 cents per round of ammunition, depending on the type. Officials say it would help offset the costs of gun violence.

One of the plaintiffs, the Bellevue-based Second Amendment Foundation, promised an immediate appeal.

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