June 5, BBC News

Seventy people have been arrested in Australia in a nationwide operation to crack down on the use of child pornography on the web.

The arrests followed a six-month investigation by police into paedophile communities online and how they trade pornographic images of children.

The probe was launched after 99 explicit pictures were posted by a hacker on a respected European website.

Over 76 hours, the site had 12 million hits from 150,000 users in 170 nations.

More than 2,800 internet protocol (IP) addresses were traced back to Australia and then identified by police.

Those arrested include a federal policeman and several teachers, reports say.

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Australian Federal Police Commissioner Mick Keelty said that investigations were ongoing and there would be more arrests in the coming days.

Investigators had worked both with international partners and state police in what Mr Keelty described as one of Australia's largest single operations against images that show child sex abuse.

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image: Explicit images have been posted on legitimate websites (SPL)