The operation, which was code-named "Barcela", followed a seven-month investigation involving the Obscene Publications and Internet Unit -- part of the Metropolitan Police's Clubs and Vice Unit. Fifteen search warrants were executed in the action, which involved 11 different police forces.
The arrests were made under the Protection of Children Act 1978.
The police arrested four men, aged 32, 28, 23 and 20, at two addresses in London, and also seized computer equipment at both addresses.
The Metropolitan Police said that Barcela concentrated on those who use the Internet to distribute indecent images of children, and that these latest arrests showed the police were determined to clamp down on this illegal practice.
"This type of crime involves one of the most vulnerable groups in society and we will take every step we can to protect them," said Chief Inspector Chris Bradford of the Clubs and Vice unit. "I want to make it very clear that offenders can no longer hide behind the anonymity of the Internet technology. We can and will trace and identify you," he added.
