According to to a human rights report released on Wednesday, North Korea has publicly executed at least seven people in the past decade for watching or distributing K-pop videos from South Korea, The New York Times reports.

The Seoul-based Transitional Justice Working Group has interviewed 683 North Korean defectors since 2015 to help map state-sanctioned public executions and burials; they have reportedly documented 23 since Kim Jong-un’s rise to power a decade ago.

Of the seven documented executions for watching or distributing K-pop, all but one took place between 2012 and 2014 in Hyesan, a major trading hub on the border with China that has become the main gateway for outside information and South Korean entertainment smuggled in on USB sticks.

Kim Jong-un recently called K-pop a “vicious cancer” capable of corrupting young North Koreans’ minds and behaviors. North Korea’s state media warned that the unchecked influence of South Korean pop culture would make North Korea “crumble like a damp wall.”