New York City Monday opened another avenue of attack in its fight against illegal guns, announcing a federal lawsuit against 15 out-of-state stores the city claims have sold dozens of weapons that were later used in crimes.

The complaint, filed in the Eastern District of New York, alleges that the dealers knowingly or negligently sold firearms to “straw” buyers who acted at the behest of others who would have been barred by federal law from buying handguns, such as convicted felons. Their acts, the suit says, have contributed to a public nuisance that endangers New Yorkers.