CNN has aired a documentary on North Korea's human rights situation containing a video clip of a public execution.

The clip broadcast Monday showed a man charged with helping a defector cross into China shot to death and scenes of a concentration camp for political prisoners.

In an interview with a South Korean reporter, a dissident said a movement opposed to the communist regime is spreading across the country, and showed a desecrated poster of the North's leader Kim Jong-il.

CNN producer Sarah McDonald, who directed the documentary, quoted a man who escaped from the concentration camp that 95 percent of prisoners die there.