The number was nearly double what MySpace officials originally estimated last year, said North Carolina Attorney General Roy Cooper, who along with Connecticut Attorney General Richard Blumenthal has led efforts to make social networking Web sites safer for young users.

Cooper said he wasn't surprised by the updated numbers, and demanded that MySpace and rival online networking site Facebook which claim to have more than 280 million users combined do more to protect children and teenagers.

"These sites were created for young people to communicate with each other. Predators are going to troll in these areas where they know children are going to be," Cooper said. "That's why these social networking sites have the responsibility to make their sites safe for children."

The attorneys general received agreements last year from MySpace and Facebook to push toward making their sites safer.

Both sites implemented dozens of safeguards, including finding better ways to verify user's ages, banning convicted sex offenders from using the sites and limiting the ability of older users to search members under 18.