North Korea has confirmed it has successfully conducted its fifth nuclear test.
North Korean state television said the test was part of Pyongyang’s response to international sanctions following tests earlier this year.
South Korean ministers have held a national security meeting.
“We are facing a serious situation that is totally different from the situations in the past in which North Korea conducted nuclear test every three years. North Korea’s nuclear and missile threats are a real, clear threats to us. Our military should maintain full readiness under a firm South Korea-US joint military defence, to strongly punish North Korea for any provocations.”
AFP news agency (@AFP) 9 septembre 2016
It follows earlier nuclear test and long-range rocket launch in January and February.
Tests suggest this is the most powerful nuclear test conducted by North Korea to date.
At 20 to 30 megatonnes, Friday’s reported test is larger than the nuclear bomb dropped by the US on the Japanese city of Hiroshima in the Second World War.
It would also be potentially bigger than the one dropped on Nagasaki soon afterwards.