SEOUL, Sept. 9 (UPI) -- North Korea announced Friday that it had successfully completed a test of a nuclear warhead hours after seismic monitors identified a 5.3-magnitude quake near the country's China border.
Pyongyang's 10-kiloton explosion was twice as powerful as the blast that took place in January at the Punggye-ri nuclear site, according to Seoul's spy agency.
The magnitude of North Korea's Friday blast now approximates the historic Hiroshima bomb that measured 12.2 kilotons and killed 100,000 people.
Veteran announcer Ri Chun Hee, who often reappears for important events, reported the nuclear test on state television only four hours after the quake was detected.
Ri said the "nuclear test improved the status of [North Korea] as a nuclear power state and demonstrated our utmost strength, to provide, should they provoke us, a realistic countermeasure to the United States and hostile countries who are viciously falling over themselves in a show of power."
North Korea's fifth test has taken the world by surprise, including ordinary North Koreans, according to China's Xinhua news agency.
According to Xinhua's Pyongyang news bureau, North Koreans in the streets of Pyongyang were unaware of the state's plans for a fifth test until the televised announcement.
Hours before the update, North Korea's capital appeared to be preparing for the celebration of its annual foundation day, but there was no large-scale event being held at Kim Il Sung Square.
North Koreans on the streets who were interviewed by Xinhua said the event was unexpected.
The test is drawing strong reactions from Pyongyang's traditional allies, and Beijing's foreign ministry said Friday China will support the denuclearization of the Korean peninsula and constructive ways to prevent nuclear proliferation at the United Nations Security Council.
In Moscow, Russian Foreign Minister Sergey Lavrov condemned the test, calling it a serious threat to stability in Northeast Asia.
All Security Council resolutions must be implemented, Lavrov said, according to RIA Novosti.