The swastika imprints left behind by the Polar Fox boot. Photo: Imgur.com.

A California-based company has apologized for and recalled a line of boots with treads shaped like swastikas, after a customer posted a photo of the footwear’s soles online.

Announcing the recall, Conal International Trading released a statement on its website saying it is “extremely sorry for the frustration” caused by the “offensive symbol” on its Polar Fox boots.

The statement continued:

The design was not intentional and was a mistake made by our manufacturers in China. There was never any intention to include any offensive designs on the products we import. We will be investigating the issue. Conal International Trading, Inc. does not promote hate or discrimination of any kind. Again, we deeply regret that this item caused offense and apologize for the mistake.

Conal International said it became aware of the issue after seeing a photo of the treads posted by a customer on Reddit, with the caption, “There was an angle I didn’t get to see when ordering my new work boots.”

The company’s e-commerce manager, Anthony Nguyen, told the UK’s Daily Mail that the swastikas were “obviously a design flaw,” and that Conal is working to determine how the mistake occurred.

Customers have shared their displeasure and shock with the bungled design in Amazon reviews, including one who wrote, “I have a hard time believing that this wasn’t intentional.”