Harry Potter author JK Rowling has been accused of "cultural appropriation" over the first part of her new series of writings on the history of magic in North America.
Her history of the 14th to 17th century was released on the Pottermore website on Tuesday and quickly came under fire for placing Native American customs among her wizarding world.
The Press Association reports that Dr Adrienne Keene of the Cherokee Nation, who is a post-doctoral fellow in Native American studies at Brown University, an Ivy League research university in Rhode Island, was critical of Rowling's work.
Dr Keene wrote in a blog post on her website Native Appropriations: "Native spirituality and religions are not fantasy on the same level as wizards. These beliefs are alive, practised, and protected."
She took particular issue with Rowling's claims that 'skin walkers' - people who could shapeshift into animals in Navajo lore - are actually Animagi - known to Harry Potter fans as wizards or witches that can turn into animals.
The Pottermore post read: "The legend of the Native American 'skin walker' - an evil witch or wizard that can transform into an animal at will - has its basis in fact.
"A legend grew up around the Native American Animagi, that they had sacrificed close family members to gain their powers of transformation."
In response to one Twitter user's question, "Were the skin-walkers evil or not? Or were they simple animagus?", Rowling replied: "In my wizarding world, there were no skin-walkers. The legend was created by No-Majes [non-magical people] to demonise wizards."
Keene responded: "It's not 'your' world. It's our (real) Native world. And skin walker stories have context, roots, and reality."
In the blog post, she added: "We fight so hard every single day as Native peoples to be seen as contemporary, real, full, and complete human beings and to push away from the stereotypes that restrict us in stock categories of mystical-connected-to-nature-shamans or violent-savage-warriors.
"How in the world could a young person watch this and not make a logical leap that Native peoples belong in the same fictional world as Harry Potter?"
Keene's comments were backed by many on Twitter.
Angela Semple replied to Rowling's tweet: "Except skinwalkers are a part of real Indigenous knowledge. I am disgusted and disappointed by your lack of respect for us."
Debbie Reese, of the Nambe Owingeh tribe, called Rowling's writing a "misrepresentation" of the culture.
"It is clear that she is writing as an outsider who is using Native story/imagery for her own purposes. Not ok," she added.
Another Twitter user wrote: "When authors use other cultures in their fictional stories without respect or consideration, they feed racism and oppression, hurting POC [people of colour]."
Aaron Paquette tweeted: "And so another generation has to grow up fighting through another non-Indigenous author's definition of who they are to society."
Another sarcastically wrote: "Hey, is it cool if I just lump this part of your tribal legends under 'animagi'?... The answer was pretty obviously going to be 'No'."
Rowling has yet to respond to the claims.