Computers are being checked for pornography
People accused of downloading child pornography from the internet have been arrested across the world in an "unprecedented" global operation, according to officials from the UK's National Crime Squad (NCS).
Police had been monitoring regular users of internet news groups specialising in explicit images of child pornography.
Intelligence gathered during the 10-month operation showed there were "dozens" of newsgroups carrying illegal paedophile images, said an NCS spokesman.
The countries with the most suspected users of the material were the US, Russia and the Netherlands.
Interpol distributed information to countries with the suspects and following two meetings in Lyon and London, the raids were launched.
It is one of the first major law enforcement operations using technology which can help to identify victims and locations, British police said.
Special computers are being used to facially map the victims, whose profiles are then added to a database which will show whether they have been used in any other images.
The technology can also help identify whether the children are related or whether images of children of different ages are in fact the same child at different stages in their lives.
It is also able to recognise whether the pictures were taken in the same location.
'Disturbing'
Detective Sergeant Doug Bewley of Britain's Scotland Yard said: "Any piece of child pornography is an example of child abuse.
"Behind these people there could well be organised gangs," he said.
Detective Superintendent Peter Spindler, heading the operation for the NCS, said it was "particularly disturbing" that the paedophile images on the news groups were available for even children to access.
"We also learnt, not surprisingly, that those abusing the internet have learnt from recent police successes how best to protect their true identities."
Sergeant Bewley told the BBC: "There is no anonymity on the internet for anybody who deals with this disgusting material.
"It is a serious offence and any persons being found involved in it will be arrested and will be dealt with."
Eight people have been arrested in the UK so far.
The files of more than 400 suspects could not be traced because they left no electronic trail.