Former Ku Klux Klan leader David Duke has been permanently banned from Twitter after breaking the platform’s rules regarding hate speech.

It's unclear what exactly Duke tweeted that prompted the prohibition, but the company said the decision was due to “repeated violations of the Twitter rules on hateful conduct,” according to ABC News.

The platform's hateful speech policy prohibits promoting violence, inciting harm or threatening attacks against people based on religious affiliation, race, ethnic origin and other protected categories.

“You may not promote violence against or directly attack or threaten other people on the basis of race, ethnicity, national origin, caste, sexual orientation, gender, gender identity, religious affiliation, age, disability, or serious disease,” the policy states.

Twitter stated these guidelines were put in place so everyone is able to share “without barriers” and because experiencing abuse on the platform will make people hesitant about posting.

“Our role is to serve the public conversation, which requires representation of a diverse range of perspectives,” the company explained. “We are committed to combating abuse motivated by hatred, prejudice or intolerance, particularly abuse that seeks to silence the voices of those who have been historically marginalized.”

Twitter defines violent threats as “declarative statements of intent to inflict injuries that would result in serious and lasting bodily harm, where an individual could die or be significantly injured.”

The site has a zero-tolerance policy for violent threats and said accounts violating that policy will face immediate and permanent suspension.

“Slurs, epithets, racist and sexist tropes, or other content that degrades someone” is prohibited as well.

Twitter recently updated its guidelines on links, which now includes hateful conduct and violence.