A Port Perry, Ont. park is closed after several dogs were poisoned by tainted cupcakes scattered on the ground.

Police in Durham region were called to Poplar Park on Ash Street at around 11:30 p.m. after at least three separate dog owners brought their pets to a local animal clinic when they became sick.

The owners said the dogs were in the park earlier that evening and ingested cupcakes that were left on the ground near a tree. Each dog became ill soon after eating the food.

The veterinarian at the animal clinic told police the dogs likely ingested a substance similar to anti-freeze, such as windshield wiper fluid.

Since the park was closed and news of the tainted cupcakes were made public, more people have come forward with a sick pet. Police are investigating reports that two more dogs were poisoned by the leftover food.

Investigators say they are not sure if the cupcakes were left in the park by someone who had an intent to poison local animals.

"It's just awful, I just can't even imagine it," one woman told CTV Toronto Tuesday morning while walking her dog.

Another dog owner choked back tears as she spoke of the news.

"I can't believe anyone would do this," she said.

Authorities searched Poplar Park and other playgrounds in the area but didn't find any other poisonous substances.

A park near an elementary school was closed while police investigated the incident to ensure children did not come into contact with the poison, said authorities.

The pets are in stable condition and are expected to recover.

Police say they want to speak with people who may have information on who placed the cupcakes in the park. Investigators can be reached at 1-888-579-1520 ext. 2686.