Facebook is teaming up with Microsoft in a bid to drive paedophiles away from its service.
Facebook will implement a Microsoft technology to automatically trawl photos posted by users for child abuse.
Microsoft's PhotoDNA technology is run by the National Center for Missing and Exploited Children (NCMEC), based in Virginia. The organisation has collected 10,000 images of child abuse from law enforcement authorities to serve as the basis of PhotoDNA, and has millions more on file.
Computers divide the images into smaller sections and calculate a hash, or digital fingerprint, for each. The hashes are shared with web services such as Facebook, which can then automatically compare them to images uploaded by users.
According to Bill Harmon, a lawyer in Microsoft's digital crimes unit, PhotoDNA detects child pornography with "zero false positives".
"Some images become 'popular' and are used time and time again - making good targets for the PhotoDNA program," the Telegraph quoted him as saying in a post on the Microsoft blog.
PhotoDNA is just the latest of several safety initiatives launched since by Facebook.
"Even though NCMEC is a US-based organization, we found image matches on our services stemming from abuse that has occurred across many countries, including the US, UK and Brazil among others," said Harmon.
"We hope that Facebook's adoption of PhotoDNA serves as a springboard for other online service providers to take advantage of the opportunity available through NCMEC's PhotoDNA program and, in fact, we know that others are exploring the possibility right now," added Harmon.