North Korea 'executes official in charge of nuclear test site'

Hermit state recently conducted sixth and most powerful nuclear test

North Korean leader Kim Jong-un said to have purged a second high-ranking official within a week (AFP/Getty Images)

North Korean leader Kim Jong-un has reportedly executed the official responsible for the country's nuclear test site.

Park In-young was the chief of Bureau 131, a division of the ruling Workers Party of Korea's Central Committee tasked with supervising military facilities such as the Punggye-ri nuclear test facility and the Sohae Satellite Launching Station.

The official was dismissed and then executed as part of a recent purge, an unnamed North Korean defector told Japanese newspaper Asahi Shimbun.

Two potential reasons were given for the reported execution.

Mr Park could have been blamed for North Korea's sixth and most powerful nuclear test being delayed, the defector said. The test was originally planned to take place in Spring, but was pushed back to 3 September due to delays in tunnel construction.

Experts have warned a series of tremors and landslides near the nuclear test facility probably mean the country's latest nuclear blast has destabilised the region, and the Punggye-ri nuclear site may not be in use much longer.

Chinese scientists have warned that if the whole mountain collapsed, radiation could escape and drift across the region.

It is also possible Mr Park was held responsible for the reported collapse of a tunnel in October, which killed around 200 people, though North Korea has denied the reports.

It comes a week after another high-ranking North Korean official, Hwang Pyong-so, was reportedly expelled from the party for taking bribes.

The military boss' deputy, Kim Won-hong, was also said to have been detained and sent to a prison camp.