Facebook is to work with Microsoft, Twitter and YouTube to slow the spread of extremist content online by creating a shared database of deleted posts.
The social network said the companies would work together to "help curb the spread of terrorist content online" by pooling deleted content into a single database that would enable extreme posts - including terror group recruitment videos - to be more quickly identified across different platforms and removed.
In a blog post announcing the collaboration, Facebook said the "shared industry database" would consist of content that was each given a 'hash' or unique digital fingerprint that would help the various sites better and more quickly identify potentially extremist content on their platforms.
"Our companies will begin sharing hashes of the most extreme and egregious terrorist images and videos we have removed from our services - content most likely to violate all of our respective companies' content policies," the post said.
"Participating companies can add hashes of terrorist images or videos that are identified on one of our platforms to the database. Other participating companies can then use those hashes to identify such content on their services, review against their respective policies and definitions, and remove matching content as appropriate."
Social media has been criticised in the past for enabling terror groups - including so-called Islamic State - to spread propaganda and recruit individuals to their cause.
The firms were also accused of falling short of a pledge to act on abusive content within 24 hours by the EU's justice commissioner, Vera Jourova.
The group of companies added that user privacy will be maintained during the sharing process.
"No personally identifiable information will be shared, and matching content will not be automatically removed," the firms said.
"Each company will continue to apply its own policies and definitions of terrorist content when deciding whether to remove content when a match to a shared hash is found.
"Throughout this collaboration, we are committed to protecting our users' privacy and their ability to express themselves freely and safely on our platforms.
"We also seek to engage with the wider community of interested stakeholders in a transparent, thoughtful and responsible way as we further our shared objective to prevent the spread of terrorist content online while respecting human rights."