Facebook is banning posts that deny or distort the Holocaust and will start directing people to authoritative sources if they search for information about the Nazi genocide.

Facebook CEO Mark Zuckerberg announced the new policy today, the latest attempt by the company to take action against conspiracy theories and misinformation ahead of the U.S. presidential election three weeks away.

The decision comes amid a push by Holocaust survivors around the world who lent their voices to a campaign targeting Zuckerberg beginning this summer, urging him to take action to remove Holocaust denial posts from the social media site.

Coordinated by the Conference on Jewish Material Claims Against Germany, the #NoDenyingIt campaign used Facebook itself to make the survivors’ entreaties to Zuckerberg heard, posting one video per day urging him to remove Holocaust-denying groups, pages and posts as hate speech.

The testimonials coincided with an advertising boycott by companies pushing Facebook into taking a stronger stand against various forms of hate speech and extremism around the world.

Facebook said today that the new policy “is supported by the well-documented rise in anti-Semitism globally and the alarming level of ignorance about the Holocaust, especially among young people.” Surveys have shown some younger Americans believe the Holocaust was a myth or has been exaggerated.

Tech companies began promising to take a firmer stand against accounts used to promote hate and violence after a 2017 rally in Charlottesville, Virginia, where a self-described white supremacist drove into a crowd of counterprotesters. Yet Facebook and other companies have been slower to respond to posts that amplify false information, but don’t pose an immediate threat of violence or other physical harm.

Zuckerberg said in a blog post today that he believes the new policy strikes the “right balance” in drawing the lines between what is and isn’t acceptable speech.

“I’ve struggled with the tension between standing for free expression and the harm caused by minimizing or denying the horror of the Holocaust,” he wrote. “My own thinking has evolved as I’ve seen data showing an increase in anti-Semitic violence, as have our wider policies on hate speech.”

Zuckerberg had raised the ire of the Claims Conference, based in New York, and others with comments in 2018 to the tech website Recode that posts denying the Nazi annihilation of 6 million Jews would not necessarily be removed. He said he did not think Holocaust deniers were “intentionally” getting it wrong, and that as long as posts were not calling for harm or violence, even offensive content should be protected.

After an outcry, Zuckerberg, who is Jewish himself, clarified that while he personally found “Holocaust denial deeply offensive” he believed that “the best way to fight offensive bad speech is with good speech.”

The Anti-Defamation League said it was relieved by today’s shift but criticized Facebook for taking nearly a decade after the New York-based group first began to publicly call on the company to curb Holocaust denial in 2011. The group tracked more anti-Semitic incidents in the U.S. last year than at an any time over the past four decades, and has said it continues to find Holocaust denial groups on Facebook, some hidden and most private.

“While Facebook has made numerous positive changes to its policies since that time, it stubbornly had held onto this outrageous platform policy, even in the face of the undeniable threat of growing antisemitism and antisemitic violence around the world,” the group’s CEO, Jonathan Greenblatt, wrote in a blog post.

The Claims Conference today said it welcomed Zuckerberg’s changed approach and the company’s decision to take action after its campaign of survivor testimonials.

“It’s a very important statement and it’s a building block toward ensuring that this sort of anti-Semitism is not amplified,” said Greg Schneider, the group’s executive vice president.

The group on Sunday posted its 75th video from a Holocaust survivor appealing directly to Zuckerberg. Fred Kurz, an American who was born in Austria in 1937, described losing both of his parents in concentration camps.

Zuckerberg never met directly with the group but Schneider said he believes the voices of survivors and their “moral authority” made a difference.

“Honestly, I’m a little surprised it took 75 days, but I’m glad it happened,” he said.

Facebook said today it would immediately begin removing Holocaust denial posts from Facebook and Instagram, which it owns, but it could take some time to train the company’s technical systems and human moderators to enforce it on a global scale.

Several other groups that had pushed for Facebook to take a stricter line on Holocaust denial said today’s move was an important step.

“Facebook is showing that it recognizes Holocaust denial for what it truly is — a form of antisemitism and therefore hate speech,” Ronald Lauder, president of the World Jewish Congress, said in a prepared statement.

Yad Vashem, Israel’s national Holocaust memorial, said it supports Facebook’s new initiative to direct its users to “credible and fact-based” information about the Holocaust, such as the memorial’s website.