A day after North Korea said it tested a nuclear device and seismic sensors worldwide registered tremors consistent with a small test, the question remains: what exactly happened at that mountain site near the Chinese border?
Many scientists and most governments concerned have yet to definitively conclude whether it was a small nuclear device, a dud test of what might have been a much larger device, or even a non-nuclear explosion.
"There is no clarity at all at the moment," said defence analyst and physicist Andrew Davies from the government-funded Australian Strategic Policy Institute.
In South Korea, the presidential spokesman quoted chief national security adviser Song Min-soon as saying: "It will take about two weeks to make a comprehensive assessment."
Japan's foreign minister Taro Aso said Tokyo wanted "proof that such a test took place" before weighing new sanctions on North Korea.
A US official said it could take several days for intelligence analysts to determine what exactly happened, and China, while working on the assumption that the blast was nuclear, has offered no details.
Even the head of the preparatory commission for the Comprehensive Test Ban Treaty Organisation, which operates an international nuclear test monitoring system, seemed still to be sitting on the fence.
In a statement Volodymyr Yelchenko expressed "profound consternation at the announcement" of the test and urged Pyongyang not to "engage in any nuclear testing".
