KCNA the official news agency said, "We have successfully conducted another nuclear test on May 25 as part of the republic's measures to strengthen its nuclear deterrent."
It added that the test would "contribute to defending the sovereignty of the country and the nation and socialism and ensuring peace and security on the Korean Peninsula." The US Geological Survey said it had detected a magnitude 4.7 tremor in North Korea at 0954 local time on Monday, May 18, indicating that a nuclear test may have taken place. It located the epicentre of the tremor about 375km north-east of the North Korean capital, Pyongyang.
Meanwhile South Korea called an emergency meeting to discuss its response. Sources say that North Korea have enough plutonium to make eight nuclear bombs.
The news of nuclear test came amidst the escalating tensions on the Korean peninsula and following North Korea's controversial rocket launch in Apr. The rocket launch resulted in more stringent action against North Korea. In return North Korea said it was pulling out of nuclear disarmament talks and restarting its weapons programme.