The vow came after a gunman killed 51 people at two mosques in Christchurch in March while broadcasting his rampage live on Facebook via a head-mounted camera.

“The dissemination of such content online has adverse impacts on the human rights of the victims, on our collective security and on people all over the world,” the signatories said in a statement.

Facebook in particular has faced withering criticism since the Christchurch attack, after the horrific footage was uploaded and shared millions of times despite efforts to remove it.

According to the blog post, Facebook said that it would be applying what it called a “one strike” policy to Facebook Live that would ban users who violate the platform’s community standards once from using the live-streaming service for set periods of time. This applies to content posted elsewhere on the website, not just streamed on Facebook Live. If a user were to post a harmful link on their profile, like content which leads to a terrorist website, they would be banned from live-streaming as well.

The social media giant, which participated in crafting the new commitments, said earlier Wednesday that it would tighten access to its livestreaming feature.

Google and its YouTube unit also joined the pledge, along with Twitter, Wikipedia, Dailymotion and Microsoft.

The companies said they would cooperate on finding new tools to identify and quickly remove extremist content, such as sharing databases of violent posts or images to ensure they don’t spread across multiple platforms.

They also said they would explore tweaking their algorithms to prevent violent or hateful content from going viral, while making it easier for users to report harmful posts.

“For the first time, governments, international organisations, companies and digital agencies have agreed on a series of measures and a long-term collaboration to make the internet safer,” Macron’s office said in a statement.

But it will be up to companies to develop specific tools or policies.

– ‘Before harm is done’ –

The largely symbolic initiative is intended to keep up the pressure on social media companies, which face growing calls from politicians across the world to prevent their platforms from becoming stages for broadcasting extremist violence.

“We need to get in front of this (problem) before harm is done,” Ardern told CNN in an interview Wednesday. “This is not just about regulation, but bringing companies to the table and saying they have a role too.”