Kim Jong-un fears for his own position with the North Korean regime, according to Bruce Bennet, a leading defence researcher at the RAND Corporation think tank.

Dr Bennet said: “He is paranoid. Purges are escalating, on an accelerated basis. He has picked up the purges, which shows he is worried about his position.”

According to the researcher, Kim Jong-un fears the existence of a “rival faction” within the regime aligned to Kim Han-sol, the eldest son of his brother Kim Jong-nam, who was assassinated with a nerve agent in a Malaysian airport last February.

Last year, seven North Korean spies were caught by Chinese authorities trying to assassinate the 22-year-old.

Dr Bennet said the country’s dictator had never been frightened like he is now by the Trump administration.

Earlier this week, General Vincent K Brooks, commander of US Forces in Korea, said the purges were prompted by defections occurring “in areas where we do not generally see them” including the heavily guarded Demilitarised Zone (DMZ).

He said: “We’re seeing some increase in executions, mostly against political officers who are in military units, for corruption.

“This is about trying to clamp down as much as possible on something that might be deteriorating and keeping it from deteriorating too quickly.”

Pyongyang has been struggling in the wake of a wide range of sanctions over its missile and nuclear programs.

This month, the US issued new sanctions on North Korean and Chinese firms said to be financing the Pyongyang regime.

Despite the sanctions, Pyongyang is preparing to stage a major military parade to mark the 70th anniversary of the founding of its military.

The event is expected to be held just one day before the opening ceremony of the Pyeongchang Winter Olympics in South Korea.