TORONTO -- Animal activists are demanding that international puppy mills be banned from importing dogs into Canada, after dozens of puppies were found dead in the cargo area of an international flight that landed at Toronto's Pearson International Airport Friday.

Pictures and videos uploaded to Facebook reportedly show hundreds of puppies in crates being loaded onto a flight at Ukraine’s Kyiv International Airport.

The woman who recorded the footage, Abby Lorenzen, said she was there to pick up a cat when she heard dogs "screaming."

"That airline should have never taken on so much live animals to begin with,” Lorenzen wrote on Facebook.

“Those animals didn’t need to suffer, coming over here for greed money flooding the markets with sick animals."

The flight landed 12 hours later with 38 dogs dead on arrival and dozens of others sick and dehydrated.

The Canadian Food Inspection Agency, which oversees the import of animals, confirmed in a statement on Friday that the Ukraine International Airlines flight landed in Toronto on June 13 with 500 dogs in the cargo load.

According to activists, dogs shipped onboard these flights usually come from puppy mills and are crammed onboard with limited space, and no water or food for hours.

Animal rights activists say puppy mills ship thousands of purebred puppies from Ukraine and other eastern European countries to Canada to be sold for thousands of dollars online on websites such as Kijiji.

According to Paws for Hope, a Canadian animal welfare foundation, the breeding mill industry is a multimillion-dollar business in Canada, with many puppy mills also being run on Canadian soil.

Activists warn that the industry will continue if consumers continue to purchase dogs from non-reputable websites.

Humane Society International spokesperson Rebbecca Aldworth says there have been several instances where dogs who are shipped from these mills die within a few days of arriving on Canadian soil.

“Animal welfare is always second to profit,” Aldworth told CTV News. “I have been in facilities where dead and dying animals are in the same cages. No food, no water… and they never get out of their cages.”

Aldworth says the surviving puppies from the flight were quickly picked up by brokers to be sold. More died after leaving the airport.

Ukraine International Airlines said in a Facebook post on Friday that they are investigating the incident to “make any changes necessary to prevent such a situation from occurring again.”