CLAYTON, Mo. (AP) — A coalition of 12 municipalities has filed a lawsuit challenging a St. Louis County ordinance regulating police standards.

The St. Louis Post-Dispatch reports that the municipalities, which include Clayton, Webster Groves and Florissant, filed the suit Thursday to block legislation that could place oversight of policing guidelines in the hands of County Executive Steve Stenger.

The ordinance was enacted last month and went into effect this week.

The lawsuit says the county has no authority over municipal police departments and that the ordinance is “illegal and unconstitutional.”

Stenger said Thursday that the ordinance is lawful and necessary.

He says maintaining police standards falls under the protection of public health, which permits the county to impose benchmarks on law enforcement agencies governed by autonomous city councils and boards of aldermen.