Credit card details given to a child pornography site in the US led the the arrest of 12 people in north Wales on Wednesday morning.

North Wales Police said a number of the people arrested came from households where children were present.

Deputy Chief Constable Bill Brereton warned of more arrests

Officers seized a large quantity of material from the properties, and warned that up to 26 more arrests were expected.

Eleven of the arrested men have been released on police bail pending further inquiries.

The twelfth is still being held for questioning at a police station in north Wales.

The raids were made after officers followed up details of customers who had subscribed to child pornography websites on a pay-per-view basis.

Detective Inspector Andrew Jenks-Gilbert said credit card details had led police to the suspects.

There is evidence that a significant proportion of people involved in child abuse online are themselves actual abusers

Detective Superintendent Chris Corcoran

"The difficulty in these kinds of circumstances is that companies providing that kind of material require payment.

"That needs some kind of credit card payment or other method of payment," he said.

"People can't get away from that and the credit card transactions are verified in the normal way, and to that extent they are not anonymous and we can find them.

"There are children in some of the addresses that are subject to the warrants, and that is a priority.

"We are working very closely with family protection units."

Detective Superintendent Chris Corcoran, who is heading the investigation, said the operation had been a success.

"We need to ensure there is no place for paedophiles who reside in north Wales to hide their criminal activities and today's arrests are testimony to this," he said.

'Growing problem'

The operation, codenamed Triumph, follows a similar investigation - Operation Ore - conducted last year.

In 2001 authorities in America informed the National Crime Intelligence Service that US-based websites were selling images of sexual abuse .

Many of the internet sites had been visited by British citizens including some from north Wales.

Mr Corcoran said: "Operation Triumph is only one part of the North Wales Police's response to this growing problem nationally.

"There is evidence that a significant proportion of people involved in child abuse online are themselves actual abusers.

Further arrests

"Using the sophisticated technology now available to us, along with traditional detective and analytical work, we can now identify these people who presumably thought their activities could remain undetected."

Deputy Chief Constable Bill Brereton said their operations will continue.

"We are actively investigating at least 26 other cases," he said.

"We will be arresting those people in similar operations very soon."