North Korea has announced it successfully tested a hydrogen bomb amid reports of a tremor near the main nuclear test site.
A state news television newsreader said, “The republic’s first hydrogen bomb test has been successfully performed at 10:00 am on January 6, 2016, based on the strategic determination of the Workers’ Party.”
This announcement came after after monitors detected a 5.1 magnitude quake close to the Punggye-ri site.
The North has conducted three nuclear tests since 2006.
Its leader Kim Jong-un last month said Pyongyang had developed a hydrogen bomb, although international experts were sceptical.
This development would mark a major, and alarming, step forward in the isolated country’s nuclear development, as hydrogen bombs generally more powerful than nuclear bombs.
A hydrogen, or thermonuclear device, uses fusion in a chain reaction that causes a much more powerful explosion than the fission blast generated by uranium or plutonium.
A hydrogen bomb uses fusion to create a blast far more powerful than that of a more basic atomic bomb.