SEOUL, Sept. 12 -- A massive explosion on North Korea's northern border with China generated an expansive mushroom cloud on an important commemorative anniversary of the Pyongyang government on Sept. 9. The blast came as concerns have been recently mounting in U.S. intelligence circles that North Korea was about to conduct a nuclear test.
Details of the blast remained sketchy, but the date of the blast -- taking place on a day commemorating the 1948 founding of North Korea -- had U.S., South Korea and Japanese officials scrambling to study satellite images of a clear picture of what might have caused the massive blast. North Korea is known to put great importance on historic dates, using such days to conduct high-profile military exercises and parades. On Sunday, U.S. officials would not rule out a potential nuclear test, but officials at Seoul's Unification Ministry -- its government agency that deals directly with the North Koreans -- said the blast appeared to be "non-nuclear" in nature.
But Bush administration officials were closely monitoring the reports Saturday night. One official in Washington said the Americans were examining satellite images of a mushroom cloud -- reported to be as large as 2.5 miles in diameter -- and that further information had been provided to the U.S. government by a diplomatic source in Beijing. However, the official said the explosion did not take place at the location that had been closely monitored in recent weeks by U.S. intelligence agencies involving suspicious movement of vehicles that some analysts believed indicated preparation for a nuclear test.
Various South Korean media sources quoted unnamed diplomats in Beijing and Seoul as saying the explosion -- reportedly larger than a chemical blast near a train station in North Korea last August that killed 150 -- took place in North Korea's Kim Hyong Jik county inside the northern Yanggang Province near its mountainous border with China. In 1998, a North Korea defector provided information to South Korean and U.S. intelligence officials that the Pyongyang government keeps a missile launching facility, leading to some speculation in Seoul that the explosion may have involved a missile accident. The location of the blast also led some analysts to discount a nuclear test, given that it took place so close to North Korea's border with its closest ally, China.
"We understand that a mushroom-shaped cloud about 2.2 miles to 2.5 miles in diameter was monitored during the explosion," South Korea's semi-official Yonhap news agency quoted an unidentified diplomatic source in Seoul as saying.
Japanese government officials monitoring the reports were scrambling for details but said existence of a mushroom cloud alone could not be taken as a clear indicator a nuclear test, saying such a formation could also be the result from other high-temperature blasts of other sorts.
On April 22, train wagons at a railway station exploded in the North Korean town of Ryongchon, killing 150 people and injuring an estimated 1,300, according to the North Korean official estimate. The perimeter of that accident was two kilometers wide. The blast was believed to have been sparked by a train laden with oil and chemicals that hit power lines.
The source in Beijing that told Yonhap about the explosion last week said it was reportedly bigger than the train explosion in Ryongchon.
Kessler reported from Washington. Special Correspondent Joohee Cho contributed to this report.