A source said some allegedly had Bibles in their possession, and all were treated as political dissidents.

The victims of the atrocity were members of the Unhasu Orchestra as well as singers, musicians and dancers with the Wangjaesan Light Music Band. They were accused of videotaping themselves having sex and selling the videos. The tapes have apparently gone on sale in China as well.

Sources in China said singer Hyon Song-wol as well as Mun Kyong-jin, head of the Unhasu Orchestra, were arrested on Aug. 17 for violating North Korean laws against pornography and were executed in public three days later.

Kim Jong-un's ex-girlfriend was among a dozen well-known North Korean performers who were executed by firing squad on Aug. 20, reports said Wednesday.

Kim met Hyon about a decade ago, before either of them was married. But he was later ordered to break off the relationship by his father Kim Jong-il and she married a soldier. Since then there have been rumors that the two were having an affair.

Kim's wife Ri Sol-ju was also a member of the Unhasu Orchestra before she married him. Whether she had any hand in the executions is unclear. The Unhasu Orchestra and Wangjaesan Light Music Band have apparently been disbanded due to the latest scandal.

"They were executed with machine guns while the key members of the Unhasu Orchestra, Wangjaesan Light Band and Moranbong Band as well as the families of the victims looked on," the source said.

The source added that all of the families of the executed appear to have been sent to prison camps under North Korea's barbaric principle of guilt by association.

Hyon was a singer with the Pochonbo Electronic Ensemble, which is famous for revolutionary and propaganda songs and one of North Korea's most popular bands. Mun won first place in an international competition in Hungary in 2005 and was decorated by the North Korean state.

Kim Jong-un was last year seen at a performance that featured Disney characters and versions of Western songs, stoking hopes that the young leader is more open to ideas from overseas, but that was apparently a misreading.

A source said, "Kim Jong-un has been viciously eliminating anyone who he deems a challenge to his authority." The executions "show that he is fixated on consolidating his leadership."

