Seoul, South Korea — South Korean police said Thursday they've arrested four people on suspicion of secretly taking videos of about 1,600 guests in hotel rooms and posting or streaming them on the internet. The Korean National Police Agency said mini spy cameras were set up in TV set-top boxes, hair dryer cradles or electrical outlets in hotels in central and southeastern South Korea.

Speaking to the BBC, Korean police said the men set up a 1-millimeter lens cameras last August in 30 separate hotels across 10 South Korean cities. A police statement accused the men of earning about 7 million won ($6,210) in total by posting or livestreaming the video on an overseas-based internet site between last November and early March.

In this Wednesday, March 20, 2019 photo, a police officer demonstrates mini-spy cameras installed at hair dryer, as he is shown on a screen, center rear, at a police station in Seoul, South Korea. Yun Dong-jin / AP

If convicted, the two main suspects could face up to seven years in prison, according to police.

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One of the suspects allegedly installed the cameras after entering the hotels as a guest. The other was accused of launching and managing the now-shuttered website. The other two were allegedly involved in buying the spy cameras or funding the internet site's operation, according to police.

The men reportedly posted 803 videos and evaded the law by basing the website server overseas, the BBC reported.

Police said they are the first people arrested in South Korea for allegedly livestreaming the private lives of hotel guests via an overseas-based website.

The illicit distribution of videos taken by hidden cameras is a serious social problem in South Korea. Thousands of women joined rallies in Seoul several times last year, demanding stronger government measures against the spread of such videos.

The country saw more than 6,000 cases reported in 2017, the BBC reported. More than 5,400 people were arrested for spy camera related crimes in 2017, but fewer than 2 percent were sent to jail.

In a separate case, South Korean police on Thursday arrested K-pop singer Jung Joon-young over allegations that he illegally shared sexually explicit videos of women taken without their knowledge or consent.

The Seoul Central District Court issued an arrest warrant for Jung hours after he appeared at a hearing and apologized to the victims and to "everyone who has showed affection for me." He was later escorted to a police station in downtown Seoul in handcuffs.