DENVER – The city of Boulder faces a federal lawsuit over claims that its “assault weapon” ban, which was passed Tuesday night, violates the U.S. and state constitutions.

The lawsuit had been expected, as Mountain States Legal Foundation stated Tuesday it planned to challenge the city’s new laws if the city council passed the measures. The council voted 9-0 in favor of the ban, which also raised the legal age of gun ownership to 21.

Mountain States Legal Foundation filed the lawsuit Wednesday on behalf of Boulder media personality Jon Caldara, the Boulder Rifle Club, the LLC behind Bison Tactical, and Tyler Faye – a 20-year-old gun owner who says his rights are being violated because of the new age rules.

The group filed the suit in the U.S. District Court of Colorado in Denver. The defendants named in the suit include the city of Boulder; its city manager, police chief, mayor and mayor pro tem, and seven city council members.

The new “assault weapon” ban, Ordnance 8245, passed in a unanimous council vote Tuesday after weeks of discussion, readings and amendments.

The ordinance defines an “assault weapon” as semi-automatic rifles with pistol grips or thumbhole stocks, or a folding stock, or a stabilizing grip for the non-trigger hand. Semi-automatic shotguns with similar features are also included under the definition.

Also included are semi-automatic pistols that have secondary grips or can accept magazines somewhere other than the customary grip.

It also added new definitions for “illegal weapons” and “large-capacity magazines,” which are defined as an ammunition feeding devices that accepts more than 10 rounds, except for pistol magazines that accept 15 rounds and some other exceptions.

Under the rules, if a person living in Boulder owned an “assault weapon” before June 15, they will have until Dec. 31 to get a background check, get a weapon ownership certification from the police department and find safe storage for the weapon.

If they don’t meet those conditions, they would have to remove the weapons or magazines from the city, turn them into the police department or render the weapon inoperable. Breaking the rules would result in a misdemeanor.

“Ordinance 8245 and the actions of Defendants violate multiple provisions of the U.S. Constitution, including Article VI, the First Amendment, the Second Amendment, the Fifth Amendment, and the Fourteenth Amendment,” the lawsuit claims.

The plaintiffs also claim the city’s new ordinance violates the state constitution and state statutes.

They are asking the court to permanently enjoin the defendants from enforcing the new ordinance and for the court to declare the ordinance in violation of the state and U.S. constitutions, as well as for compensatory damages and other reasonable costs, should they be successful.

When reached for comment Thursday, the Boulder City Attorney’s Office said it did not comment on pending litigation.