Nearly three dozen pet cats housed in an upstate New York shed have died in a fire.

The Niagara County Sheriff's Office says the 34 cats were discovered by firefighters responding to a blaze Saturday morning. It's unclear what sparked the fire. Fire marshals are investigating.

Officials haven't named the homeowner. But the sheriff's office says the resident dialed 911 after noticing flames in the 12-by-20-foot structure in the front yard of the rural property in Porter, about 15 miles north of Niagara Falls.

Niagara County SPCA shelter manager Kelley Casale says the residence had no history of animal cruelty complaints.

She says the homeowner likely took in strays but failed to neuter and spay them, causing the cats to multiply. She calls the fire deaths horrific.