Thirty-three North Koreans face execution after being charged with attempting to overthrow the repressive regime of Kim Jong-un.
The Koreans have landed themselves in hot water after it emerged they had worked with South Korean Baptist missionary Kim Jung-wook and received money to set up 500 underground churches. It is understood they will be put to death in a cell at the State Security Department.
Experts believe the North Koreans are being punished more harshly than usual as North Korean leader Kim Jong-un combats a wave of dissatisfaction at the regime's isolationist "juche" doctrine.
Missionary Kim Jung-wook was arrested and jailed last year for allegedly trying to establish underground churches. Last week he held a press conference at which he apologized for committing "anti-state" crimes and appealed for his release from North Korean custody.
He told reporters that he was arrested in early October after entering the North from China and trying to make his way to Pyongyang with Bibles, Christian instructional materials and movies.
Kim Jung-wook said he had received assistance from South Korea's intelligence agency.
"I was thinking of turning North Korea into a religious country, and destroying its present government and political system," he said at the time.
"I received money from the intelligence services and followed instructions from them, and arranged North Koreans to act as their spies. And I also set up an underground church in China, in Dandong, and got the members to talk and write, for me to collect details about the reality of life in North Korea, and I provided this to the intelligence services."
A South Korean intelligence source in China took issue with Kim's account, saying that the missionary did not enter North Korea voluntarily, but was kidnapped by agents of the Pyongyang government in China.
During Kim Jung-wook's press conference, North Korean officials also showed video of North Koreans who confessed to coming into contact with the missionary.
The North Korean newspaper Chosun Ilbo reported that they said that Kim told them to build a church on the site where a massive statue of North Korea's founder, Kim Il-Sung, stands in Pyongyang whenever the regime falls.
North Korea continues to hold Korean-American missionary Kenneth Bae, who was detained while leading a group on a tour of North Korea in 2012 and later sentenced to 15 years of hard labor. Bae was moved to a hospital last summer in poor health, but said at the news conference that he was being transferred back to prison.