The new policy will ban "videos alleging that a group is superior in order to justify discrimination, segregation or exclusion," the company said in a blog post. The prohibition will also cover videos denying that violent incidents, like the mass shooting at Sandy Hook Elementary School in Connecticut, took place.

YouTube did not name any specific channels or videos that would be banned.

"It's our responsibility to protect that, and prevent our platform from being used to incite hatred, harassment, discrimination and violence," the blog post said.

The decision by YouTube, which is owned by Google, is the latest action by a Silicon Valley company to stem the spread of hate speech and disinformation on its site. A month ago, Facebook evicted seven of its most controversial users, including Alex Jones, the conspiracy theorist and founder of Infowars. Twitter barred Mr. Jones last year.