US shoe company recalls boot that 'mistakenly' leaves swastika imprints.

A California shoe company has apologised and recalled a boot after a customer realised the sole’s tread left behind swastika imprints.

The boot, made by Conal International Trading Inc, went viral after a Reddit user posted a photo of it leaving behind a swastika print.

“There was an angle I didn’t get to see when ordering my new work boots,” the post read.

Conal has since pulled the boot and issued an apology, saying the design was “not intentional” and “a mistake” by manufacturers in China.

“We were informed recently the company imported boots that have an offensive symbol designed on them,” the company said.

“There was never any intention to include any offensive designs on the products we import.”

Conal said it did “not promote hate or discrimination of any kind” and was investigating what had gone wrong.

The Reddit post, which has been viewed more than three million times, sparked a flurry of jokes on social media.

On Amazon, where the boots were sold before being pulled by the company, users left reviews describing the boots as “good for marching into Poland, but not so much for anything else”, and rating them a “nein out of ten”.

Other Reddit users pointed out the boot style shared its name — Polar Fox — with that of the codename for a German and Finnish military operation in World War II.

This post originally appeared on ABC News.