HARRY Potter author J.K. Rowling has come under attack and caused another social media sensation, this time based on claims by Native Americans that she has appropriated their culture.

Rowling is writing three pieces on her Pottermore website to describe the history of magic in North America as seen through her fictional world of Harry Potter.

She has based some of her work on the real and ancient Navajo tradition of “skin walkers” who are akin to shape-shifters, and that has upset members of the tribe and other Native Americans.

The controversy has by coincidence arisen at the same time as the trailer has appeared for the film of Rowling’s first screenplay, Fantastic Beasts and Where to Find Them, which is due out in November.

Dr Adrienne Keene, a Cherokee who is a researcher at Brown University, Tweeted: “It’s not “your” world. It’s our (real) Native world. And skin walker stories have context, roots, and reality. You can’t just claim and take a living tradition of a marginalised people. That’s straight up colonialism/appropriation.”

Keene also wrote: “What you do need to know is that the belief of these things (beings?) has a deep and powerful place in Navajo understandings of the world.

“It is connected to many other concepts and many other ceremonial understandings and lifeways (sic). It is not just a scary story, or something to tell kids to get them to behave, it’s much deeper than that.”

Brian Young, whose Twitter identity is @hungrynavajo, tweeted: “I’m broken hearted. Jk Rowling, my beliefs are not fantasy. If ever there was a need for diversity in YA lit it is bullish!t like this.”

Though Rowling has yet to tweet an answer, plenty of her supporters have taken to social media to defend the author.

One user tweeted that Keene’s arguments were “sophomoric at best, idiotic at worst,” and another said Rowling’s detractors were “social justice warriors,” an American derogatory term for people with socially progressive beliefs.