North Korea's nuclear weapons capability

North Korea is thought to have produced enough plutonium for about six to eight weapons and has already produced one rudimentary nuclear device. It likely cannot miniaturize a nuclear weapon to mount on a missile and would need a significant amount of testing to master the technology, weapons experts say. Further , its nuclear arms program is not a major security threat at present because it has not yet shown it can build an effective bomb, nor does it have an effective delivery system.

The biggest security threats posed by the North come from its hundreds of mid-range missiles, which can hit all of South Korea and most of Japan, as well as its artillery batteries posted close to its border with the South. Jane's Defence estimated the North could rain 500,000 shells an hour into the Seoul area, which is home to about half of South Korea's 49 million people.

A North Korean first strike with artillery and rockets, which may also carry biological weapons or material to spread radiation poisoning, would cause major damage to South Korea and Japan, which in turn would deal a heavy blow to the global economy.