The Portland City Council approved an ordinance amendment Monday night prohibiting the sales of pets from puppy and kitten mills in the city.

Councilors passed the ordinance on first reading, which means it must go before the council a second time before it can be enacted. The ordinance would prohibit retail sales of dogs and cats, unless they come from an animal care facility or rescue organization.

City officials said the Legislature passed a puppy and kitten mill bill in 2015 but the bill was vetoed by Gov. Paul LePage. Supporters of the legislation have turned to cities and towns to provide leadership on the issue.

“Although there currently are no retail stores selling dogs or cats in Portland, the passage of this ordinance will prohibit any in the future,” the city staff wrote in a memo to the council.

A puppy mill is a large-scale commercial dog breeding facility where profit is given priority over the well-being of dogs, according to the American Society for the Prevention of Cruelty to Animals.