South Korea believes one of its Christian missionaries has been held in North Korea for more than four months as claimed by the communist country, officials said Thursday. Kim Jung-wook, who appeared in a rare news conference in Pyongyang earlier in the day, is believed to be the same person whom the North has called a South Korean spy, they said. North Korea claimed in November that it had arrested a spy of South Korea's National Intelligence Service (NIS), who sneaked into the country with the purpose of inciting dissent, without identifying the name of the alleged spy. The alleged spy's name had not been officially confirmed until Thursday when Kim held a news conference in Pyongyang. In Pyongyang, Kim asked that North Korea release him, saying he is sorry for his anti-state crimes, according the Associated Press. Kim said he was arrested on Oct. 8, just a day after he crossed into the North from China and tried to make his way to the North Korean capital with Bibles, Christian instructional materials and movies, AP reported from Pyongyang. Kim also claimed he met with South Korean intelligence officials numerous times and received thousands of dollars from them and followed their instructions before entering the North, according to AP. In Seoul, the NIS said it has nothing to do with Kim.