Defectors and other campaigners in South Korea have for decades sent anti-North Korean leaflets over the tightly guarded border, usually by balloon or in bottles on border rivers. They also send food, medicine, money, mini radios and USB sticks containing South Korean news and dramas.
Isolated North Korea has long denounced the practice and recently stepped up its condemnation of it, to the alarm of a South Korean government intent on improving ties on the divided peninsula.
