North Korea has conducted a nuclear test today, South Korea's
defence ministry said, after seismic activity measuring 4.9
magnitude was registered by the US Geological Survey.
The epicentre of the seismic activity, which was only one km
below the Earth's surface, was close to the North's known
nuclear test site.
"We've been informed by the South Koreans that there's been a
(North Korean) nuclear test," a UN Security Council diplomat
told Reuters on condition of anonymity.
An international nuclear test monitoring agency said the
location of the seismic event was "roughly congruent with"
2006 and 2008 tests carried out by the reclusive state and
had "clear explosion-like characteristics".
North Korea, which had been threatening a third nuclear test,
had informed Beijing and Washington on Monday of plans to
undertake a test, South Korea's Yonhap news agency reported.
The isolated state, which is banned under UN Security Council
resolutions from developing nuclear and missile technology,
did not make any immediate comment.
North Korea is not prone to seismic activity and it may take
hours or even days to determine officially whether a nuclear
test had been conducted.
South Korea's defence ministry said the North Korean seismic
event could be the result of a 6-7 kiloton or stronger
nuclear blast. South Korea's President Lee Myung-bak called a
national security council meeting for 0400 GMT.
North Korea successfully launched a long-range rocket in
December in violation of U.N. resolutions that banned it from
developing missile or nuclear technology after nuclear tests
in 2006 and 2009.
It announced plans for a third nuclear test in response to
the sanctions imposed in January after the rocket launch,
although satellite imagery indicated it has been readying its
test site for more than a year.