While a response of condemnation kept US President Barack Obama working well past midnight and into early Monday morning, just hours later he laid a memorial wreath at the Tomb of the Unknowns at the military's burial grounds, Arlington National Cemetery, to commemorate Memorial Day, and then played more than four hours of golf.
The notice about the upcoming test from
"Less than one hour" later, the 0100 GMT explosion
was registered by the US Geological Survey, close to the site of
"We have also seen the North Korean claims of the size
of the test and note that in 2006
The US government said the characteristics that were recorded suggested an explosive yield of "approximately a few kilotons" of TNT. Added analysis was being carried out over the coming days.
Stressing the "importance of a strong, unified approach," US Secretary of State Hillary Clinton
spoke with her Japanese and South Korean counterparts in the six party talks about the test and was to talk with the Chinese and Russian foreign ministers in the course of the day.