New Zealand Prime Minister Jacinda Ardern and French President Emmanuel Macron have launched an initiative to tackle the spread of violence and extremism online.
Seventeen countries and some of the world’s biggest tech companies have signed up to the Christchurch Call, a three-page document containing a series of voluntary pledges to prevent uploads of hateful and violent content, and quickly remove any that gets through their defences.
Eight nations who did not attend Wednesday's talks, including Germany, Australia and India have signed the pledge.
"Cooperative measures to achieve these outcomes may include technology development, the expansion and use of shared databases... and effective notice and takedown procedures," the declaration read.
In particular they promised "immediate, effective measures to mitigate the specific risk that terrorist and violent extremist contest is disseminated through livestreaming."
The US State Department confirmed it will not sign up, but said it was in broad agreement with the goals of the call.
The move to secure pledges from firms and world leaders comes just months after a white supremacist gunman used Facebook Live to stream his rampage at two mosques in the New Zealand city of Christchurch, killing 51 people.
The live stream was broadcast live by the gunman on Facebook for 17 minutes and remained online for a further 12 minutes before Facebook was alerted by a user and took it down, but millions of uploads and shares of the video continued in the following days.
Ms Ardern asked for international assistance to solve the issue. "It's a global problem that requires a global response," she said.
Before the conference kicked off in earnest, Facebook had already pledged to ban Facebook Live users who shared extremist content and work to reinforce its own internal controls to stop the spread of offensive videos.
"Following the horrific recent terrorist attacks in New Zealand, we've been reviewing what more we can do to limit our services from being used to cause harm or spread hate," Facebook vice-president of integrity Guy Rosen said in a statement.
"There is a lot more work to do, but I am pleased Facebook has taken additional steps today," Ms Ardern said in a statement.
Ms Ardern also asked world leaders in attendance, including the UK’s Theresa May, King Abdullah of Jordan and Canada’s Justin Trudeau, to act responsibly when finding a balance between regulation and their citizens’ freedoms.
"Online, we as governments may choose regulation as a tool to address this issue. But we need to recognise that regulation alone will not solve the problem. We need to work collectively with tech companies, with civil society, to make meaningful change,” she said.
"Where we regulate, these regulations must not become a barrier to a free, open and inter-operable internet. We must maintain and support an internet that acts for good."
The pledge is separated into three sections - one for governments, one for tech firms and another for how the two can work together to meet the common goal of eliminating the spread of online extremism.