Miniaturised nukes

North Korea appears to have achieved "a significant level" of technology to miniaturize nuclear warheads to fit on its ballistic missiles that could potentially reach the US mainland, South Korea's Defense Ministry said Tuesday, Yonhap News Agency reported.
The assessment was included in the 2014 edition of the ministry's biennial white paper released on the day, which highlights North Korea's evolving nuclear and missiles threats to the region and beyond after its third and most recent nuclear test in 2013. It was the first time that the paper carried a technological analysis of the North's nuclear program, with the previous edition simply outlining the country's two underground detonation tests conducted in 2006 and 2009. "North Korea's capabilities of miniaturizing nuclear weapons appear to have reached a significant level," the paper said.
"North Korea is presumed to have secured some 40 kilograms of weapons-grade plutonium by reprocessing spent nuclear fuel roads multiple times, and it is evaluated to have been working on the highly enriched uranium program." Pyongyang has yet to demonstrate the miniaturization capability, though officials and experts from South Korea and the US have said the country is believed to have the technology to build nuclear-tipped missiles. In the paper, South Korea also assessed that North Korea is "presumed to have (missiles) capabilities that could threaten the US mainland, having fired off long-range missiles five times." In an apparent move to strengthen defenses along the border and to better protect its military facilities, North Korea has set up a new corps-scale military unit in its North Hamkyong Province upon the instruction of its leader Kim Jong-un, according to the defense paper.
As of October 2014, North Korea had 1.2 million regular service personnel, some 10,000 more than two years ago, while South Korea has around 630,000 service members, the paper said.