It also comes ahead of an online-extremism summit in Paris cochaired by New Zealand's prime minister, Jacinda Arden, and France's president, Emmanuel Macron.
The companies said they would also commit to publishing "transparency reports" on the detection and removal of terror or violent extremist content. Copies of the video spread rapidly across Facebook, YouTube and Twitter, with the social media companies struggling to remove them all.
Starting Wednesday, people who break Facebook's "most serious policies" will be immediately banned from using Facebook Live for a period of time, such as 30 days.
In addition to these new restrictions, Facebook also pledged to invest $7.5 million in research to better detect manipulated images and videos.
The largely symbolic initiative is meant 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. "It will be up to each country and company to decide how to carry out the commitments, according to two senior New Zealand officials involved in the drafting, who spoke on the condition of anonymity because the exact wording of the pledge was still being finalized", according to the Times.
User Reporting of Terrorist and Violent Extremist Content.
"Companies like Facebook are becoming more aware and more willing to make reforms than the US, and they're doing it purely on grounds of public opinion", Knott said.
The changes are in response to the recent terrorist attacks in New Zealand.
The policy will expand to other topics in the coming weeks, and the company says it will stop the same offenders from purchasing ads.
"This may include using algorithms and other processes to redirect users from such content or the promotion of credible, positive alternatives or counter-narratives", the Christchurch Call to Action document says.
In the immediate aftermath, Ardern and New Zealandpassed new gun control measures and introduced some legislation that would ban most semi-automatic weaponry.
Wednesday's event, two months to the day since the Christchurch massacre in New Zealand, drew up a "plan of action" to be adopted by countries and companies to prevent extreme material from going viral on the internet.