The leader of one of South Korea's biggest online sex networks has been sentenced to 40 years in prison, reports said Friday.

Cho Ju-bin was charged with blackmailing 74 women, including minors, into filming sexually explicit videos and posting them on pay-per-view online chat rooms. Authorities called the sex abuse ring "virtual enslavement."

According to the Seoul Central District Court, the 25-year old convicted sex offender "distributed sexually abusive content that he created by luring and threatening many victims," the Yonhap news agency quoted it saying.

Court representative Kim Yong-chan said Cho was convicted of violating the country's child protection laws and operating a criminal organization. Cho "disclosed the identities of many of his victims and inflicted irreparable damages to them."

South Korea prosecutors initially demanded a life sentence for Cho on the basis of the "irreparable damage" he inflicted on his victims, the Telegraph reported.

Cho was found guilty of "instructing a third party to rape a victim, who was a minor," the court ruled.

Cho hosted online sex chat forums through encrypted messaging app Telegram where some users paid up to $1,200 to see minors perform sexual acts under duress. At least 10,000 people use the chat rooms - with some paying in cryptocurrency to watch the sex videos, officials say.

On Thursday, the Seoul court sentenced five of Cho's associates - one of them a 16-year-old - to up to 15 years in prison.

Cho's case sparked widespread outrage in South Korea because of a culture some experts say is too forgiving about sexual abuse.

Following a series of investigations into similar sexual violations, authorities said more than 120 suspects had been arrested since 2019 and at least a dozen other leaders of internet sex rings had been jailed.