Humane agents raided a property north of Pittsburgh tonight, finding hundreds of dead and dying cats in what may be the largest animal seizure in Pennsylvania history.

Howard Nelson, director of the Philadelphia-based Pennsylvania SPCA, which orchestrated the raid, said as many as 1,000 cats could ultimately be removed from Tiger Ranch, located in Tarentum, about 20 miles from Pittsburgh.

"It's a death camp," said Nelson, speaking by cell phone as he helped gather emaciated and diseased cats crammed into trailers and other outbuildings across the 30-acre property. "I see cats that can't walk, and dead cats in litter boxes and lying by food bowls."

Nelson said many of the cats have severe respiratory illnesses and others are infected with diseases that cause blindness.

A team of more than 100 people, including law enforcement officers, humane agents, veterinarians and volunteers, entered the property about 7:15 p.m., Nelson said.

What they found stunned even veteran humane agents.

"The vast number of animals and the degree of neglect is astounding," said Reba McDonald, a humane officer with the SPCA.

The raid was expected to last all night and into tomorrow as agents worked to trap the cats and deliver them to medical teams for assistance.

An emergency shelter was set up at the Clarion County SPCA to handle the vast number of animals.

Humane officers said the owner, Linda M. Bruno, would be charged with multiple counts of animal cruelty.

Bruno was at the site when the raid started and was being questioned late tonight by state police troopers, Nelson said.

Nelson, speaking 90 minutes after the raid began, said Bruno was already facing 13 counts of cruelty connected to the first 17 cats seized.

Tiger Ranch - which, on its Web site, www.tigerranch.org, bills itself as "a cat sanctuary where mercy triumphs" - took in thousands of stray and unwanted cats a year from individuals and high-kill shelters from nine states.

But Nelson called it "a classic hoarding situation."

Postings on Internet message boards suggest that rescues from as far away as Georgia shipped cats to Tiger Ranch and that Philadelphia rescues also sent cats there.