Earlier this month, a South Korea-based activist group claimed it had sent 20 balloons carrying anti-Pyongyang leaflets and USB sticks containing Korean pop music and music videos across the border.

In July, South Korea started boosting broadcasts of K-pop songs and propaganda messages across the two countries' heavily armed border into North Korea in response to the balloon drops.

North Korean defectors have been known to send balloons to the North side containing anti-regime leaflets, and have also reportedly sent USB memory sticks of Korean pop music and videos ...