"This church exists in the very deep underground," the VoM spokesman Todd Nettleton said.
"To our knowledge, its members are either old people who had already been Christians before the Communist takeover and kept the faith, or very young ones who have been converted as refugees in China."
According to Nettleton, converts cross secretly from China back into North Korea to plant clandestine congregations. He said his organization, which supports persecuted Christians in Communist and Muslim countries worldwide, had no statistics about North Korean church membership.
However, the Religion Today Internet service reported that there are by some estimated 500,000 Christians in that secretive country.
UPI failed Thursday to elicit a comment from the North Korean observer mission at the United Nations in New York. Without giving his name, a spokesman said, "We have nobody here to deal with the media."
In 1998, the North Korean government allowed three Christian churches to open in Pyongyang, its capital. Two are Protestant, one is Catholic. The state-recognized Korean Christian Federation, supposedly a Protestant body, claims to have 12,000 members among a population of 23 million.
Allegedly, there are also 4,000 Catholics and 10,000 Buddhists.
But European visitors to Pyongyang reported on condition of anonymity that the Christian congregations they observed were "clearly bogus."
"We saw a rent-a-crowd obviously ordered into those churches to impress foreigners," a Western European said after his return from a recent trip to the North Korean capital. "It was obvious that the choir consisted of professional singers, who had been delegated there."
"We understand that North Korea recently reopened its seminary with 12 students," said Holly Hursh of International Christian Concern, a Washington-based advocacy group.
"We were told that huge images of (dictator) Kim Jong-Il and his father Kim Il-Sung decorated this school, while there was a much smaller picture of Jesus on a side wall."
Hursh told UPI, "We have received reports that an estimated 100,000 Christians are being held in North Korean labor camps and subjected to the worst forms of torture."
According to these reports, molten steel was poured over Christians; believers were deprived of clothes and food and treated like animals, even though article 68 of the North Korean constitution guarantees the freedom of religious practice.
There were also reports from several refugees that Christians were being executed on gallows or by firing squads in public squares.
When converts are caught returning to North Korea from China, they are usually killed immediately, the VoM's Nettleton reported. "If they are caught by the Chinese and extradited to North Korea they are incarcerated."
On the Chinese side of the border, refugees are being trained in clandestine Bible schools to plant congregations inside North Korea, Nettleton said. The education includes instruction on how to conduct church services.
According to other sources, North Korean Christians frequently send messengers across the border to inquire about proper liturgical practices, such as the celebration of Holy Communion.
Nettleton added that couriers constantly risk their lives smuggling Bibles printed in South Korea into their homeland. "Moreover, when the wind is right we send big orange balloons from China to North Korea."
The balloons, measuring 2 by 2 feet, bear the entire Gospel of Luke on one side and further Scripture readings on the other.
"When they take off," Nettleton said, "the North Korean military is put on alert, and then its units chase those vinyl bags all around the countryside."
Notable deaths of 2014 [PHOTOS]