The posting comes after the group shut down more than 40 pedophile Web sites last week that were exchanging images through an anonymous Tor network, the technology site TG Daily reported Monday.
"The owners and operators at Freedom Hosting are openly supporting child pornography and enabling pedophiles to view innocent children, fueling their issues and putting children at risk of abduction, molestation, rape and death," Anonymous said in a statement on Pastebin.
"By taking down Freedom Hosting, we are eliminating 40-plus child pornography Web sites, among these is Lolita City, one of the largest child pornography Web sites to date containing more than 100 gigabytes of child pornography."
The group then published a list of more than 1,500 names it says were users of the site.
"If the FBI, Interpol, or other law enforcement agency should happen to come across this list, please use it to investigate and bring justice to the people listed here," it says.