North Korean Security Believes Ryongchon Explosion an Assassination Attempt According to a source, North Korea's State Safety & Security Agency concluded that the massive explosion that occurred in the North Korean city of Ryongchon on April 22 had been conspired by anti-North Korean government forces to harm North Korean leader Kim Jong-il. A North Korean official who was recently on his business trip to China said, The North Korean National Security Agency has investigated the incident since it took place and concluded that rebellious forces had plotted the explosions targeting the exclusive train of Kim Jong-il. The security agency, in particular, gained evidence that cell phones had been used in triggering the explosion and reported to the North Korean leader that the use of cell phones should be banned for the sake of the leaders safety, the official said. Accordingly, it was learned that North Korea prohibited the use of cell phones across the nation on May 19. An officer working with a North Korean border guard unit, which is in charge of guarding the border area between the North and China, said in a phone call with this writer that the use of cell phones was banned in Pyongyang first on May 19, and then prohibited in other regions on May 20. A North Korea defector who crossed the border a few days ago said, It doesnt seem to be a temporary measure, because even handsets have been conscripted following the cell phone use ban. The Postal Service, which manages the cell phone business, has unilaterally conscripted handsets without offering any compensations. It's a typical example of a dictatorial state, the defector pointed out. North Korea began to use European-type GSM phones in August 2002 and started cell phone service in Najin and Sunbong, the North Korean special economic areas, starting November that year. However, in areas bordering China, an increasing number of North Korean people have already used cell phones with handsets made in China since the end of 1990s.