The intermediate range ballistic missile crashed into the city with a population of 200,000 and exploded in a failed test launch, US government sources have revealed.
On April 28, 2017, a Hwasong-12 missile test fired from the Pukchang Airfield failed after launch and hit the city of Tokchon, it is claimed.
The first stage engine reportedly failed one minute into its flight after the rocket had traveled 24 miles sending it tumbling into an area of industrial buildings causing massive damage.
It is feared that the likelihood of a repeat of the accident is high with the repeated use of untested systems.
Satellite images show damaged buildings and an area where debris was cleared from an earlier images appear to show a whole building is missing.
Due to the ultra-secretive and paranoid nature of the North Korean regime it is unknown how many if any casualties were caused by the impact.
It is predicted that just a slight change to the missile’s flight path could have seen it smash through a residential area.
Since the accident, Pyongyang has launched missiles over Japan with observers fearing another failure could see a missile accidentally hitting Tokyo or Osaka.
A similar incident taking place over Japan could spark an all-out conflict with tensions at boiling point.
The launch was one of three failed Hwasong-12 launches last April before the rocket which paved the way for the Hwasong-14 intercontinental ballistic missile which was successfully unveiled last year.
News of the costly accident comes after US President Donald Trump warned North Korean dictator he had a “bigger nuclear button”.
The US President’s tweet comes in response to North Korea’s supreme leader boasting he has a “nuclear button on his desk”.
President Trump tweeted: “North Korean Leader Kim Jong-un just stated that the ‘nuclear button is on his desk at all times’.
“Will someone from his depleted and food starved regime please inform him that I too have a nuclear button, but it is a much bigger and more powerful one than his, and my button works.”
Trump hit out with the withering attack after Kim used his annual address in Pyongyang to try and strike fear into the US.
He said: “The entire United States is within range of our nuclear weapons, and a nuclear button is always on my desk. This is reality, not a threat.”
Kim also called for his country to “mass-produce warheads and ballistic missiles”.
The dictator also declared that North Korea had reached full nuclear force in 2017 and called for the mass-production of nukes and missiles in the year ahead as tensions continue to rise with the US.
He said: “We achieved the goal of completing our state nuclear force in 2017.
”We need to mass-produce nuclear warheads and ballistic missiles and accelerate their deployment.”