International condemnation have greeted North Korea’s claim to have successfully carried out an underground hydrogen bomb test.
If confirmed, it would be North Korea’s fourth nuclear test since 2006 and mark a major upgrade in its capabilities.
But nuclear experts have questioned whether the size of the blast was large enough to have been confirmed as an H-bonb.
south Korea called the test a grave provocation but said it was difficulot to believe it was from such a device.
More powerful and advanced than atomic bombs, hydrogen bombs use fusion rather than fission to create a blast.