The Child Exploitation and Online Protection Center said predators posing as children online convinced their victims to perform sexual acts or share images, then threatened to send pictures to the victim's family and friends, the BBC reported Friday.
Over a two-year period, 424 children had been blackmailed in this way, of which 184 were in Britain, the center said.
CEOPC deputy chief executive director Andy Baker said the abuse "escalates really quickly," sometimes taking only 4 minutes "to go from, 'Hi, do you want to get naked?' to self-harming."
Seven victims have killed themselves, including a 17-year-old British teen, Baker told the BBC. Another seven victims seriously injured themselves, six from Britain.
"We're talking about a very small dark percentage of [the Internet] and this is what we need to police," he said.
In the 12 cases Baker highlighted, the abusers were from four continents. In five cases the criminals were based in Britain.
The biggest case, known as Operation K, involved the exploitation and blackmail of 322 children worldwide, including 96 in Britain. The victims, mainly boys between the ages of 11 and 15, were targeted by a gang from a non-European country. The suspects are to stand trial in the coming weeks.
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