Kim Jeong-uk, a South Korean missionary, entered North Korea on October 7th with Bibles and other religious materials in hand.
The next day, he was captured by North Korean authorities and has been held against his will ever since.
At a press conference in Pyongyang on Thursday, Kim said he had wanted to build an underground church in the North Korean capital.
"I advised to break the North Korean regime and build God's nation, and ordered them to build an underground church in the North."
North Korea claims Kim is a South Korean spy, and was plotting to overthrow the state.
This claim was backed up by Kim, who testified that he received money from South Korea's spy agency in exchange for providing information about the North.
The National Intelligence Service denied the claims Thursday, and it's worth noting that Pyongyang has a tendency to coerce statements out of its detainees.
South Korea's Unification Ministry says it was notified about the arrest in November, but that the North refused to give details on the detainee.
"It was inhumane for North Korea to continue ignoring our repeated calls to identify and repatriate the detained South Korean, and to only reveal his identity now."
The ministry demanded that the North ensure Kim's safety until he is repatriated and to allow his family and lawyer to visit him in Pyongyang.
It is rare for a South Korean national to be detained in the North, and the incident comes amid thawing inter-Korean relations.
Experts expect Kim to be released sooner rather than later, as North Korea is known to showcase its detainees before sending them back home.
But considering the unpredictable nature of the communist regime, the possibility of the South Korean missionary being used as a bargaining chip cannot be ruled out.
Hwang Sung-hee, Arirang News.