The group took credit this week for shutting down more than 40 websites used for sharing such material. It also said it exposed information about more than 1,500 users, reports .

According to a posted on text-storing website Pastebin, some Anonymous members stumbled upon a child pornography index while browsing a part of the Internet mostly used for illegal peer-to-peer file sharing that isn't seen by search engines and can't be accessed without a special browser. They then tracked most of the sites listed to a shared hosting server.

Anonymous said that after warnings to remove the illegal content went unheeded it infiltrated the server and shut down services to all users.

The hacker group boasted that one of the websites it took down was "one of the largest child pornography websites to date containing more than 100GB of child pornography."

Anonymous said it released the of that website, including usernames, how long they have been active on the site and how many images they have shared. According to the crime-related blog , the hacking group also claims to have learned the identities of some of the people on the list and have invited the FBI to contact them if they wanted the details.