YouTube has suspended the account of former Ku Klux Klan leader David Duke, CNN Business reports . Other channels have also been banned by the company, which is part of Google. This includes an account of the white supremacist Richard Spencer and his National Policy Institute.

According to YouTube, the people behind the channels have violated rules multiple times by stating that certain groups of people are naturally subordinate to others, CNN said .

The Ku Klux Klan (KKK) is one of the best known groups around the ideology of white supremacism. Supporters of this philosophy believe that people with a white skin are superior to people with a darker skin color. They believe that white people should therefore have power over this group.

Richard Spencer is a right-wing extremist who calls himself a white nationalist . In that capacity, he believes that all black people should leave the United States. The term is often used as a euphemism for white supremacism , although ideologies overlap.

Spencer has been the chair of the National Policy Institute, an alt-right lobby organization, since 2011. He has indicated on Twitter that he will appeal the suspension.

A YouTube spokesperson did not comment to CNN on specific examples that banned the accounts. The company also did not explain further why action has now been taken against the channels.

See also: Background: Where does the far-right alt-right movement come from?