Kerry said America’s basic force posture wasn’t up to debate. “There is no discussion that I know of to change that,” he said.
But he said it was logical that additional missile-defense elements, deployed specifically in response to the Korean threat, could be reversed if that threat no longer existed.
“I was simply making an observation about the rationale for that particular deployment, which is to protect the United States’ interests that are directly threatened by North Korea,” he said.
Source: As U.S. Talks Up Diplomacy, N. Korea Takes Hard Line By AP
While many threats have been dismissed as bluster, U.S. and South Korean say they believe the North in the coming days may test a mid-range missile designed to reach as far as Guam, the U.S. territory in the Pacific where the Pentagon is deploying a land-based missile-defence system.
Japan is the last stop on a 10-day trip overseas for Kerry, who visited Seoul and Beijing as well in recent days.
In South Korea, he strongly warned North Korea not to launch a missile and he reaffirmed U.S. defence of its allies in the region. In China, he secured a public pledge from Beijing, the lone government with significant influence over North Korea, to rid the North of nuclear weapons.
Before returning to the United States, Kerry planned a speech Monday in Japan on the Obama administration’s Asia policy.
Source: North Korea: U.S., Japan open door to new nuclear talks if Kim Jong Un lowers tensions By: Bradley Klapper
Although both represent roughly the same level of threat, a uranium bomb would signify a huge technological achievement - the process of distilling natural uranium ore to the stuff suitable for bombs is profoundly difficult.
The 2013 test was indeed larger in force than previous ones but monitors failed to detect radioactive isotopes, hampering efforts to fully assess the device. Eight samples had been analysed but nothing found, South Korea's Nuclear Safety and Security Commission said.
Finding certain isotopes - xenon gases in particular - would help experts determine whether a plutonium or uranium-based device was used.
But a well-contained test could yield no radioactive isotopes, experts say. It is still unclear whether the 2013 test used plutonium or uranium.
Source: Q&A: North Korea nuclear programme by Asociated Press