The US State Department released the annual report on global religious freedoms on Tuesday which showed Christians in North Korea are receiving extreme punishment for their faith such as executions, torture, beating and arrest.
It states: "An estimated 80,000 to 120,000 political prisoners, some imprisoned for religious reasons, were believed to be held in the political prison camp system in remote areas under horrific conditions."
The study confirmed there is still "an almost complete denial by the government of the right to freedom of thought, conscience, and religion..."
The report cited examples of Christians persecuted for their faith such as a pastor who was killed by North Korean agents in China close to the border where he had assisted North Koreans in defecting.
A North Korean defector who is now a member of the Seoul-based Worldwide Coalition to Stop Genocide in North Korea told the Daily Telegraph that despite the continued intolerance for Christianity in North Korea, more people are turning to religion.
He said: "In the past, the people were told to worship the Kim family as their god, but many North Koreans no longer respect Kim Jong-un.
"That means they are looking for something else to sustain their faith.
"In some places, that has led to the emergence of shamens, but the Christian church is also growing and deepening its roots there."
He added that this shows there are cracks beginning to form in the North Korean regime.
The UN estimates there are between 200,000 and 400,000 Christians in the country out of the 25.1 million population. It's estimated that there are several hundred thousand Christians practicing their faith underground.
While North Korea claims to have five state-controlled churches in Pyongyang, it's not known how many of them attend regularly.
The report states that the visitors "appear to have been brought in for the occasion... they seemed to be observers rather than participants".
Several defectors from outside of Pyongyang said they didn't know anything about these churches.