Facebook is expanding its recent crackdown on dangerous conspiracy theories to include Holocaust denial.

On Monday, Facebook announcedthat it would update its hate speech policies in order to “prohibit any content that denies or distorts the Holocaust.”

The move comes after years of pressure from Jewish groups and organizations that track hate. Facebook cited recent surges in anti-Semitism around the world (and on its own platform) as the reason for this policy change.

The social network highlighteda concerning new surveythat found that a quarter of adults in the U.S. between the ages of 18 and 39 “believed the Holocaust was a myth, that it had been exaggerated, or they weren’t sure.”

Facebook's move was lauded by some groups that have been working with the company on combating hate speech on the platform.

“By taking the critical step to remove Holocaust denial content, Facebook is showing that it recognizes Holocaust denial for what it truly is — a form of anti-Semitism and therefore hate speech,” said Ronald Lauder, president of World Jewish Congress, in a statement. “Denying the Holocaust, trivializing it, minimizing it, is a tool used to spread hatred and false conspiracies about Jews and other minorities. Today’s announcement sends a strong message that Facebook will not allow its platform to be misused to promote hate.”

World Jewish Congress’ statement notes that the organization, which says it represents Jewish communities in 100 countries, has pushed for Facebook to remove Holocaust denial from its platform for years.

Facebook has taken a much stronger stance on hate speech and harmful conspiracy theories in recent months.

The company prohibitedviolent groups, such as some U.S.-based militia organizations, from its platform in August. Just last week, Facebook bannedpages and groups pushing the QAnon conspiracy. The social media platform also expandedits hate speech policies earlier this summer to ban blackface and some Jewish stereotypes, but until today, Holocaust denial content wasn’t prohibited.

Oftentimes, these policy moves are an about-face from Facebook’s earlier public stance. When it comes to Holocaust denial specifically, Facebook founder and CEO Mark Zuckerberg previously defended the company’s decision to allow that type of content on its platform.

“I find that deeply offensive,” Zuckerberg said when asked about Holocaust denial on Facebook in a 2018 interview with Vox. “But at the end of the day, I don’t believe that our platform should take that down because I think there are things that different people get wrong. I don’t think that they’re intentionally getting it wrong.”

While the new policy on Holocaust denial is in effect, Facebook says it will take some time to train its content reviewers and automated systems to act on the new ban.