The National Rifle Association, Second Amendment Foundation and two Seattle residents are suing the city over its new gun-safety law.
News outlets report the lawsuit filed Friday in King County Superior Court alleges that the "safe storage" requirement violates Washington state law, which prevents cities from regulating guns.
Earlier this month the Seattle City Council unanimously passed the legislation proposed by Mayor Jenny Durkan.
Durkan signed the legislation Wednesday, with the law set to take effect in approximately six months.
The law says a gun owner could be fined up to $500 if a firearm isn't locked up, up to $1,000 if a minor, "at-risk person" or unauthorized user accesses the weapon and up to $10,000 if someone uses the weapon to hurt someone or commit a crime.
City Attorney Pete Holmes said the lawsuit was expected.
