If true, this would be an extremely significant step for the North Koreans to take. It would automatically ratchet up tensions in an already tense region and could force Japan to go publicly nuclear. It is thought that Japan has the technology and know how to rapidly produce a nuclear warhead - perhaps in a matter of months. A North Korean nuclear armed missile may force the Japanese to actually construct a nuclear deterrent - something China would almost certainly object to in the strongest terms.

In short, few things would be worse in East Asia than a nuclear armed North Korea with an ICBM capability.

Reuters:

"The field deployment of a nuclear missile is imminent," said Kim Tae-woo, former head of South Korea's state-run Korea Institute for National Unification, who also served as head of research at the state-run Korea Institute for Defense Analyses.

Diplomatic sources told Reuters that China, North Korea's lone major ally, had used diplomatic channels to warn North Korea against a nuclear test, another possible sign that Pyongyang is considering such a move.

Experts say the delivery vehicle of choice for the North's first nuclear warhead would most likely be the mid-range Rodong missile, which has a design range of 1,300 km (800 miles).

"Given the number of years that North Korea has been working at it, my assessment is that they can mount a warhead on a Rodong," Mark Fitzpatrick, director of the non-proliferation at the International Institute for Strategic Studies, said.

"...Also, there is no doubt that Pakistan can mount a nuclear warhead on its version of the Rodong ...It is reasonable to assume that North Korea can too. How reliable the warhead would be is another question."

A South Korean government official involved in monitoring the North's nuclear capabilities said miniaturization was "within sight".

"It is likely there has been progress, but on the question of whether they have actually achieved it, I'd have to say not yet," he said.

In March, the North fired two Rodong missiles which flew about 650 km (400 miles) before splashing into the sea off the east coast, well short of their full range.

Some experts interpreted the short flight as a test of a modified missile designed to carry a nuclear warhead by cutting the amount of fuel on board.

"A long-range missile test makes little sense for North Korea as a test to deliver a nuclear warhead," Kim said. "...if the North deploys a nuclear weapon, the strongest candidate to carry it will be the Rodong."

One major caveat: Arms control experts point out that the engineering tolerances and overcoming miniaturization challenges necessary to marry a warhead to an ICBM may be beyond the capability of a third world country like Iran and North Korea - at present. But if a country works long enough and is willing to spend the money, it is likely to succeed.

No one can really guess the timetable for North Korea or Iran to overcome the technical difficulties in order to become a truly dangerous nuclear power. So, perhaps prudence dictates that we assume that both Iran and North Korea are on the brink of achieving their goal and act accordingly. Peaceful international pressure has failed so far. Maybe it's time to seriously think about an international military coalition to prevent the unthinkable from occurring.

But the Obama administration has made a decision to pretend that Iran can be bought off from going nuclear and that North Korea's nuclear threat can be managed. In short, Obama is going to leave the question of dealing with a nuclear Iran and North Korea to his successor.

As long as neither nation launches first.