Police have kicked off a nationwide crackdown on websites and smartphone applications promoting teenage prostitution, officials said Monday.

In a bid to curb the rampant sex crimes involving teenagers, the National Police Agency said it would enhance the monitoring of websites carrying adult content, online chat applications for smartphones and peer-to-peer file-sharing services that are often used by those inciting teenage prostitution.

Investigators will especially be on the lookout for people who propose prostitution in exchange for free food and lodging, as young runaways are prone to fall to such temptations. Earlier this month, police in Gimhae, South Gyeongsang Province, took into custody four teenage girls and four 20-something men on suspicion of coercing a female high school student into prostitution and taking her earnings.

In addition to forcing prostitution, the accused allegedly physically abused the victim ― who had run away from home ― until she died, and buried her on a nearby mountain. They reportedly sought out potential clients through a smartphone application.

Investigators will also keep an eye out for potential blackmailing via naked online chats. Last year, Busan police nabbed a ring of scammers who would trick male victims into taking naked photos of themselves and blackmail them.

By Yoon Min-sik (minsikyoon@heraldcorp.com)