According to reports, North Korea has joined the elite nuclear club by detonating its first nuclear bomb earlier today.

The test came just hours after Japan and China warned the communist country against proceeding with the test.

"Our science research section has safely and successfully conducted an underground nuclear test on Oct 9," announced North Korea's official Korea Central News Agency .

"The nuclear test, conducted under in a scientific method and under specific calculations, did not cause any danger," the new agency was quoted in Bloomberg.com.

KCNA added that there was no leak or danger from the test.

Reuters meanwhile reported a statement from South Korea's presidential Blue House that a tremor had been detected in North Korea today.

The report added that South Korea's Institute of Geoscience and Mineral Resources had detected a tremor of a magnitude 3.58 to 3.7 at 0135 GMT (9.35am Malaysian time).

However, US defence officials could not confirm the the test had happened.

The US Geological Survey also said it has detected no seismic activity, such as might be expected from a nuclear test, on the Korean peninsula within the last 48 hours.

"We haven't seen any activity either seismic or otherwise within the last 48 hours on the Korean peninsula," USGS geologist Rafael Abreu told Reuters .

Arms race

North Korea announced last week it would test a nuclear device saying its hand was forced by what it called US threats of nuclear war and economic sanctions. But it said it would not be the first to use a nuclear weapon.

According to Bloomberg , North Korea now faces the prospect of the US drafting a United Nations resolution that includes the threat of military action.

The US ambassador to the UN, John Bolton, on Oct 4 pledged such a measure should North Korea detonate a nuclear weapon.

"The North Korean test may set off an arms race in the region similar to the nuclear proliferation in South Asia, where India detonated two devices in May 1998, followed in the same month by Pakistan's test of a bomb," said Bloomberg .

"The North Korean test will compound efforts to get Iran to abandon its nuclear programme, which the US and its allies say is geared toward building a bomb. Iran says its nuclear programme is intended only to produce energy," added the report.

Currently, there are five recognised nuclear powers - US, Russia, China, United Kingdom and France - and three unofficial nuclear states, India, Pakistan and Israel.

If today's nuclear test in North Korea is confirmed, it will be the ninth country to have nuclear weapons.