North Korea says it's successfully conducted a test of a miniaturised hydrogen nuclear device, marking a significant advance in its strike capabilities and raising alarm bells in Japan and South Korea.
The test, the fourth time North Korea has exploded a nuclear device, was ordered by young leader Kim Jong Un, and detonated today. (wed)
South Korean President Park Geun-Hye says her government will take all possible measures, including possible United Nations sanctions, to ensure Pyongyang pays the price after its fourth nuclear test.
(trans) "So now, our government has to take decisive measures against any additional provocations by North Korea and work with the international community to make sure the isolated country pays the price for its latest nuclear test."
However South Korea's intelligence agency says the device may not have been a hydrogen nuclear bomb, and no radiation has been detected since the test.
In December, Kim appeared to claim his country had developed a hydrogen bomb, but the United States and outside experts were sceptical at the time.
Japan, China and Britain have also strongly condemned the test.
