North Korea is cracking down heavily on any form of social or political dissent since the recent ouster of eminence grise Jang Song-taek.
North Korean authorities are spreading word of the public executions of two of Jang's confidants, who were accused of "damaging the Workers Party" in a phrase that usually means corruption.
One source said scores of people across the country were publicly executed over the past month for offenses like selling and watching South Korean movies and TV series.
"The State Security Department issued a sudden decree in early October to eradicate 'impure' broadcast materials and that led to a widespread crackdown," the source said. "Fear is spreading across all provinces."
In Chongjin, North Hamgyong Province last month, North Korean authorities publicly executed around 40 prisoners in front of 15,000 spectators, while another five were executed on the spot at the orders of a people's court. In Hyesan, Ryanggang Province, two people were executed in October. Public executions also took place around the same time in four other provinces.
Authorities are apparently forcing people to write confessions and admit their "sins" of watching South Korean movies or shows and to identify others who watched them.
State security agents and their commanding officers in Hyesan, a popular route taken by defectors, have recently been subject to harsh inspections. Authorities are apparently trying everything they can to block access to the outside world, confiscating mobile phones and setting up additional electromagnetic wave sensors in border regions to detect communication signals and any suspect move.
Barbed wire fences and booby traps have gone up along the Tumen River to prevent people fleeing the country.
One intelligence official here said North Korean authorities are trying to quell dissent by spreading word of the public executions, and the sudden sweep of South Korean films and TV shows, which used to be tacitly tolerated, is another part of the strategy.
Signs of dissent, which were always confined to a few isolated pockets, have now all but flickered out. "There are no signs of restiveness in the military" despite the recent ouster of key figures and dwindling rations, "but there is no telling what will happen in the future," the intelligence official said.