BOULDER, Colo. (AP) — Opponents have filed a lawsuit challenging Boulder's new assault weapons ban.

The Mountain States Legal Foundation filed the lawsuit Thursday, two days after city councilors passed the ban on the sale and possession of assault weapons, bump stocks and high-capacity magazines.

The lawsuit was brought on behalf of the Boulder Rifle Club, Bison Tactical, a Boulder-based maker and seller of shooting gear, and Jon Caldara, president of the Independence Institute.

The law was proposed in response to the high school shooting in Parkland, Florida.

It requires people who own magazines that hold 10 or more rounds or bump stocks to dispose of them or sell them by July 15. People who already own assault weapons will be able to keep them but must get a certificate proving prior ownership.