North Korea tests hydrogen bomb, may load onto missile: State media

Pyongyang: North Korea detonated a hydrogen bomb with "perfect success", its state media said Sunday, adding that the device was capable of being loaded onto its long-range missiles.

Hours after the North's sixth nuclear detonation, an announcer on its official Korean Central Television declared, "The hydrogen bomb test was a perfect success."

Earlier today, a 6.3-magnitude tremor struck its main testing site, which South Korean experts reportedly said was nearly 10 times more powerful than the 10-kiloton test carried out a year ago.

The explosion came just hours after the North claimed to have developed a hydrogen bomb that could be loaded onto the country's new intercontinental ballistic missile.

Hydrogen bombs or H-bombs -- also known as thermonuclear devices -- are far more powerful than the relatively simple atomic weapons the North was believed to have tested so far.

Analysts' initial estimates of the yield from Sunday`s test varied, ranging from 100 kilotons up to one megaton.

Either way, said Jeffrey Lewis of the arms control wonk website on Twitter, it was "a staged thermonuclear weapon" which represents a significant advance in its weapons program.