North Korea said it set off a hydrogen bomb Sunday in its sixth nuclear test, which judging by the earthquake it set off appeared to be its most powerful explosion yet.
Its state-run media said the country successfully tested a hydrogen bomb meant for an intercontinental ballistic missile.
The Joint Chiefs of Staff in Seoul says in a statement South Korea’s military has strengthened monitoring and readiness and is mulling a variety of possible responses that could be pushed together with its ally the U.S.
South Korea’s weather agency and the Joint Chiefs of Staff said an artificial 5.7 magnitude quake occurred at 12:29 p.m. local time, in Kilju, northern Hamgyong province, the site where North Korea has conducted nuclear tests in the past. Seoul officials revised their earlier estimate of 5.6 magnitude quake. The U.S. Geological Survey called the quake an explosion with a magnitude 6.3.
South Korea’s presidential office says the security chiefs for Seoul and Washington have spoken following North Korea’s sixth nuclear test.