The incident was not reported internationally until 12 September 2004, when the
South Korean news agency
Yonhap cited a source in
Beijing,
China, which said a
mushroom cloud had been observed. In addition, suspicion was raised by the fact that there was no mention of the explosion on internal North Korean
media. However, North Korean news is usually a method employed by governing figures to make the ruling party's decisions more favourable to the people (national and internationally); therefore, unfavourable stories are commonly not broadcast. The
Ryongchon disaster earlier in 2004 was reported only several days after the event. There was immediate popular speculation that the explosion was
nuclear in origin.
United States Secretary of State Colin Powell said there was "no indication" that it was nuclear, and
South Korea similarly said that it did not appear to be nuclear. It would be some days before the effects of a nuclear explosion would be unequivocally visible to apolitical authorities. It would not be possible to hide the nuclear nature of such an explosion for long, as the
radioactive isotopes created by a nuclear explosion would be detectable to outside observers around the world.
From North Korea North Korea initially denied that the explosion was nuclear. When prompted for an explanation, North Korea's
foreign minister,
Paek Nam-sun, officially stated that the explosion "was in fact the deliberate
demolition of a
mountain as part of a huge
hydroelectric project". North Korea announced on 13 September 2004 that the
British ambassador,
David Slinn, would be permitted to visit the site. Diplomats from the United Kingdom,
Sweden,
Germany, the
Czech Republic,
Poland,
Russia and
Mongolia visited what was purported to be the site on 16 September 2004, and reported having seen a hydroelectric project under construction. However, South Korea said the diplomats had not been in the correct location and were about 100 km (62 mi) from the suspected explosion site.
From South Korea On 17 September 2004, South Korean Vice Minister of Unification
Rhee Bong-jo claimed that there was no explosion at all at the purported site, saying the supposed mushroom cloud was a natural cloud formation (mushroom clouds form from many types of large explosions, not only nuclear detonations). On the same day, the
Korea Earthquake Research Center reported that the only seismic activity in Ryanggang province in the period in question was at 23:24
Korea Standard Time (
UTC +9) on 8 September 2004 at
Mount Baekdu, about 100 km from the suspected blast site. == North Korean disarmament talks ==