Police said Wednesday they have caught nearly 400 people in a massive crackdown on those possessing or distributing obscene materials on the Internet.

The Seoul Metropolitan Police Agency said they have arrested four, including a 31-year-old suspect surnamed Lim, for allegedly possessing and distributing child pornography and booked 393 others for similar charges without physical detention.

Internet pornography has been blamed for a recent spate of sex crimes on children and women that have triggered public uproar.

The crackdown came after police declared a war on sex crimes along with a one-month plan to intensify patrols and crackdowns on child pornography to reduce sex crimes early last week.

In a show of their strong determination against child pornography, the police later indicted around 60 people for simply possessing child porn.

Lim is suspected of possessing nude photos of teenagers whom he met through a smartphone chat service in July, the SMPA said. He is also accused of having sex with a minor.

Sixteen members of exclusive Internet cafes that posted child porn have also been booked, police investigators said. Thirteen of them have previous convictions on molesting children and raping minors, the police added.

Police said they have also booked seven operators of major local file-sharing Web sites, including a 38-year-old operator of a Web-hard service, which has more than 3 million members. (Yonhap News)