A dog was seen inside a backpack at the airport’s x-ray machine

Transportation security authorities in Wisconsin, United States, were surprised to find a dog inside a passenger’s backpack through an airport x-ray machine.

“A dog accidentally went through an X-ray,” the TSA Great Lakes Transportation Administration tweeted about the incident, which occurred this week at Dane County Regional Airport in Madison.

ABC affiliate WISN in Milwaukee said the owner forgot to report the animal to authorities in her bag. However, the tweet did not specify if she was trying to smuggle the puppy on purpose or had forgotten about the animal in her bag.

The case sparked controversy on social media. “Poor thing,” one Twitter user commented, while another raged: “This dog owner should be arrested for cruelly treating her fur baby.”

Another person accused the owner of trying to avoid taxing the pet. “It is inhumane to carry a pet in a sealed backpack, which is clearly not an airline approved to carry a pet.” He added: “Maybe she was trying not to pay the fees needed to transport the pets. She is sick.”

Amidst the controversy, TSA reminded those traveling with pets to “notify the airline and inquire about the rules.” In addition, the entity posted a video that instructs pet owners on how to properly travel with their pets.

Travel authorities explained: “At the checkpoint, remove the pet from the bag and send all items, including the empty transport box, to be tracked into the machine.” The condition of the animal after bust was not reported.