According to South Korea's defense minister, North Korea may have created a nuclear warhead small enough to be launched in a missile. This is a first for those nutters, who had previously only detonated two nuclear devices that were too big for rockets.
Today, a typical thermonuclear weapon weighs about 2,400 pounds (1,100 kg), and has a destructive capability of 1.2 megatons of TNT. Compare this to the 0.013 megatons of TNT of Little Boy, the 9,700-pound nuclear bomb dropped by Enola Gay over Hiroshima.
If South Korea is right, this type of warhead would allow North Korea to create missiles capable of reaching South Korea or Japan just few minutes after launch. These nuclear devices can use their current and tested rocket technology, completely destroying a city as large as Tokyo or Seoul.
North Korea is also working on a missile capable of reaching as far as the West Coast of the United States. According to NORAD (North American Aerospace Defense Command) and USNORTHCOM (US Northern Command), Kim Jong Il and his cronies failed on testing such a rocket in April 2009. However, the Guardian later reported that North Korea may actually be able to reach Hawaii. Whatever the outcome of those tests was, what is clear that they will not stop at that failure.