Vigilant parents and well-educated children remain the first line of defence against online predators, even as social networking sites toughen standards and police crack down, experts told a panel of U.S. governors on Sunday.

Law enforcement agencies are becoming more technologically proficient in the fight against cyberspace child stalkers, New Hampshire Attorney General Kelly Ayotte said. But they alone can't solve a problem so widespread that one in five kids who use the internet are believed to have been approached by a predator, she said.

"This is an issue that we're not going to arrest our way out of," Ayotte said during the annual meeting of the National Governors Association, held in Traverse City, Mich.

It's a problem "far bigger than any of us realize," said Gov. Brad Henry of Oklahoma.

Speakers including Miss America, Lauren Nelson, as well as Hemanshu Nigam, chief security officer for MySpace/Fox Interactive Media, called for more programs to educate parents and children about how predators operate.

"The best way to police the internet is to do it from our side of the keyboard," said Nelson, 20, who made online safety her platform because she and friends received inappropriate photographs at age 13 from a man they met online.

Posing as a teenager, Nelson took part in an April sting operation that led to charges against 11 men. She announced last month she would tour the nation with a security software company to promote the issue.

It's good for sites such as MySpace and Facebook to verify members' ages, but that should not lull parents into a false sense of security, said Richard Wistocki, an internet crimes investigator with the police department in Naperville, Ill. Instead, they should go online themselves and keep track of what their children are doing, he said.

In child predator cases, Wistocki said, parents of victims frequently tell him, "I never thought my kid would take a picture of herself naked, leave with somebody they met online, all those things. Well, if the parent doesn't go and check, how do you know?"

Nigam, a former Microsoft Corp. security officer, said MySpace has installed more than 75 safety features in the past year, including a requirement that members provide valid e-mail addresses. The minimum age for members is 14, and the site has mechanisms to weed out younger users and shield the profiles of 14- and 15-year-olds from public view.

Nudity and pornography are banned, he said, and each page provides a way to report inappropriate conduct.

"We take very seriously our responsibility to provide a safe community for our members," he said.

The company developed a database of 600,000 sex offenders and used it to identify and remove those who were registered MySpace members, he said. MySpace pledged in May to begin sharing the information with prosecutors and will look for other ways to co-operate, Nigam said.

"This for us is an ongoing battle, and for society it is an ongoing battle," he said.