Australian police have alleged that Facebook failed repeatedly to reveal the activity of an international child pornography syndicate operating on the social networking site.
The failure by the website was uncovered during a federal police-led international investigation of the syndicate, which had been using fake online identities, the Sydney Morning Herald reported Friday .
"We are aware that Facebook knew of the existence of these pages and even went so far as to remove the profiles," said the director of the Australian Federal Police (AFP) high-tech crime centre, Neil Gaughan.
But despite closing down the pages after finding illegal material, Facebook did not contact the police, Gaughan said.
"Facebook deactivated the online accounts of the initial suspects but there were indications that, within hours, the groups were re-forming again."
With the help of the FBI in the US, the Child Exploitation Online Protection Centre in Britain, and police in Germany, South Africa and Switzerland, the AFP brought down the paedophile porn ring.
While officers believe there may have been dozens of people involved in the ring, 11 men have been arrested. They include two Australian men, aged 33 and 18, and a 26-year-old British-based man who police say is the ringleader.
All 11 are accused of creating Facebook pages under false identities and using the pages to distribute and view graphic sexual images of children, the report said.
After federal police arrested one of the Australians, he stunned them by describing how he had sent up to 10 messages to Facebook allegedly informing them about the ring, but the company failed to pass the information to police.
Facebook has been criticised in the past for failing to address privacy and safety concerns held by its hundreds of millions of users.