NEW YORK, July 24 (Reuters) - Popular Internet social network MySpace said on Tuesday it detected and deleted 29,000 convicted sex offenders on its service, more than four times the figure it had initially reported.

The company, owned by media conglomerate News Corp , said in May it had deleted about 7,000 user profiles that belonged to convicted offenders. MySpace attracts about 60 million unique visitors monthly in the United States.

The new information was first revealed by U.S. state authorities after MySpace turned over information on convicted sex offenders it had removed from the service.

"The exploding epidemic of sex offender profiles on MySpace -- 29,000 and counting -- screams for action," Connecticut Attorney General Richard Blumenthal said in a statement.

Blumenthal, who led a coalition of state authorities to lobby MySpace for more stringent safeguards for minors, and other state AGs have demanded the service begin verifying a user's age and require parental permission for minors.

The minimum age to register on MySpace is 14.

"We're pleased that we've successfully identified and removed registered sex offenders from our site and hope that other social networking sites follow our lead," MySpace Chief Security Officer Hemanshu Nigam said in a statement.

The service has come under attack over the past year after some of its young members fell prey to adult predators posing as minors. The families of several teenage girls sexually assaulted by MySpace members sued the service in January for failing to safeguard its young members.

Late last year, it struck a partnership with background verification company Sentinel Tech Holdings Corp. to co-develop the first U.S. national database of convicted sex offenders to make it easier to track offenders on the Internet.

Convicted sex offenders are required by law to register their contact information with local authorities. But the information has only been available on regional databases, making nationwide searches difficult.

As of May, there were about 600,000 registered sex offenders in the United States.