Eleven cats in makeshift kennels were dropped outside the Edmonton Humane Society this week, leaving the organization to urge Edmontonians to not abandon animals outside their doors.

Workers found the cats on the morning of Dec. 28, meaning they were left outside after the organization closed its doors the previous day.

The number of cats abandoned at one time was "unprecedented" according to Anthea Smith, a veterinarian with the Edmonton Humane Society.

Smith said the cats were left in two kennels, taped cardboard boxes and two laundry baskets fastened together with zip ties.

She said leaving the cats on the doorstep is not ideal for anyone.

"If they're having trouble caring for their animal ... give us a call and we can talk about the various options for their animal," she said.

The organization is not releasing much information due to the ongoing investigation by the society's animal protection department, but Smith said the cats are now in their care.

Many cats are often abandoned over the Christmas as unwanted gifts. But Smith said the problem is consistent throughout the year.

"Unfortunately, in the animal welfare world, it's an issue we see all too often," she said. "It's an ongoing issue and it's dangerous for the animals."

Regardless of the situation, Smith suggests people always calls ahead before bringing any animals to humane society's offices.

"Please stop abandoning animals outside our doors, especially in the winter," she said.