The world's largest and most popular internet sites are in secret discussions to create a system that could wipe child abuse images from the web.
Facebook, Microsoft, Google, Twitter and at least three other companies have signed up to, or are talking about, the project which would lead to the creation of a single database.
The project is an unprecedented industry-wide effort to deal with paedophiles sharing abuse images on the web. Industry sources told the Times newspaper in London that some of the companies had signed secrecy agreements and there had been tense negotiations for about nine months.
It's believed silence was required to ensure the "rival companies could have frank discussions about the topic", the newspaper said.
The database of the "worst of the worst" images will be maintained by Thorn: Digital Defenders of Children.
Executive director of Thorn, Julie Cordua, told the Times that they wanted to clean "this horrific content off platforms" and to identify the victims.
The Los Angeles-based charity was founded by the formerly married actors Ashton Kutcher and Demi Moore.
The companies involved have adopted Microsoft's PhotoDNA software that creates a "hash" or digital signature on abuse images.