By Yi Whan-woo

Youngsters are being sent to labor camps in North Korea after being caught secretly watching South Korean entertainment ― including movies and soap operas ― according to sources familiar with Pyongyang.

The sources said the authorities were cracking down on clandestine viewing of South Korean media amid fears that it will harm the Kim Jong-un regime's "ideological purity."

The young people still risk being sent to re-education labor camps for using illegal memory cards for entertainment.

"Those who are caught are sent to youth labor-reform centers and kept there for about a year for re-education," a source said.

In his New Year's address, Supreme Leader Kim Jong-un underscored that "a vigorous struggle should be waged to tighten moral discipline throughout society, establish a socialist way of life and eliminate all kinds of non-socialist practices, so as to ensure that all the people, possessed of ennobling mental and moral traits, lead a revolutionary and cultured life."

Kim Jong-un enjoys K-pop concert in Pyongyang [PHOTOS] 2018-04-01 21:37  |  North Korea
South Korea media is becoming increasingly popular in the secretive state, according to defectors.

Oh Chong-song, 24, a soldier who made a daring dash across the Demilitarized Zone in 2017, said he was a big fan of K-pop band Girls' Generation.

Meanwhile, the U.S.-based Human Rights Foundation said it was helping North Korean defectors to flood their former homeland with flash drives full of news bulletins and documentaries to counter state propaganda there.

In an interview with the British paper The Telegraph, the foundation's strategy officer Alex Gladstein said up to 10,000 flash drives were smuggled across the border last year.

Waging this information war is "the only way to inspire change," he said. "So it's really like a third way, and this is to liberate minds."