North Korea has reportedly seen a surge in incurable diseases and radiation deaths after it carried out its fifth nuclear test, reports Daily Mail.

Last month the secretive state triggered a magnitude 5.3 earthquake with a successful explosion which drew immediate condemnation from North Korea's neighbours and Washington.

Now those living close to the Punggye-ri nuclear site, in the north-east of the country, are paying the price for the nuclear tests, a defector has claimed.

The defector told the Daily Star: 'Mantapsan mountain is becoming a radioactively contaminated site due to the government's nuclear craze. The people who drink the water are suffering various incurable diseases, foetal deformities and an unusually high death rate.'  

Kathryn Higley, head of Nuclear Science and Engineering at Oregon State University, said it was 'definitely a possibility' the North's underground tests had irradiated the groundwater.

Last month, North Korea confirmed it had conducted its most powerful nuclear test to date, marking the 68th anniversary of its founding.  

The North said the latest test had been of a 'nuclear warhead that has been standardised to be able to be mounted on strategic ballistic rockets'.

Estimates of the explosive yield of the latest blast have varied. 

South Korea's military said it was about 10 kilotonnes, enough to make it the North's 'strongest nuclear test ever'. 

Other experts say initial indications suggest 20 kilotonnes or more. 

Hiroshima's 15 kilotonne blast obliterated five square miles of the city and killed around 100,000 people. 

South Korean President Park Geun-hye said the test was a clear violation of security council resolutions and accused Kim of 'maniacal recklessness'.   

North Korea is under an international ban on developing and testing nuclear and missile technology - but has flouted that several times in the past few years.

The country aims to develop a nuclear-armed missile that could reach the US mainland.