North Korea said on Sunday it has successfully tested a hydrogen bomb designed to be mounted on its newly developed intercontinental ballistic missile, producing a greater yield than any of its previous nuclear tests. The hydrogen bomb test ordered by leader Kim Jong Un was a “perfect success” and was a “meaningful” step in completing the country’s nuclear weapons programme, state television said. The announcement came hours after a large earthquake that appeared to be man-made was detected near the North’s known nuclear test site, indicating that the reclusive country had conducted its sixth nuclear test.