A record number of children under 18 years old fell victim to crimes involving social networking services in 2013, the National Police Agency said in a report.
The number of victims rose by 271, or 20 percent, from the previous year to 1,293, the highest since comparable data became available in 2008.
The figure was over 1,000 for the fifth year in a row.
In particular, a sharp increase was seen in the number of children who became victims after downloading free communications applications such as Line and KakaoTalk and posting identification codes assigned to their smartphones on bulletin boards designed to exchange the IDs to start communication by email and phone.
The research found that fewer children had become crime victims through game and SNS websites. It is believed that smartphone apps have quickly become key tools for those who prey on minors, the police said Thursday.
Users of Line and Kakao Talk apps can talk and exchange emails using ID exchange bulletin boards, making it unnecessary to exchange phone numbers and email addresses.
The police first noticed the link between child prostitution and pornography and ID exchange bulletin boards in 2012, when 36 children were recognized as victims.
In 2013, the number of victims stood at 352, up 9.8-fold from the year before, the police said.
Of these, 232 were Line users and 85 Kakao Talk users.
Upon a police request, Line Corp., the Line operator, had banned ID use by minors under 18 by the end of 2013.
But KakaoTalk operator Kakao Japan Corp. has yet to introduce restrictions on ID use, the police noted.
To prevent cybercrimes involving minors, police across the nation last year began meeting with and cautioning minors offering compensated dating and underwear for sale over the Internet.
In the April-December period, police met with 158 minors, eight of them boys, who averaged 15.8 years old. The youngest of them was a 13-year-old junior high school student, the agency said.
The figure included 97 high school students, 32 other junior high school students and 23 minors not in school or employment.
One in three had never been in trouble with the police before, the agency said.