SEOUL May 20 North Korea, which this month
threatened to carry out a fourth nuclear test, may be closer
than previously thought to putting a nuclear warhead on a
missile, some experts say, making a mockery of years of U.N.
sanctions aimed at curbing such a programme.
North Korea has long boasted of making strides in acquiring
a "nuclear deterrent", but there had been general scepticism
that it could master the step of miniaturising a nuclear warhead
to mount on a ballistic missile.
No one outside the inner circle of North Korea's nuclear
programme likely knows what advances the country has made. But
there has been a shift in thinking by some who study North Korea
full time since it conducted a nuclear test in February last
year and amid on-off indications it is preparing another.
The isolated and poverty-stricken state, which regularly
threatens to destroy the United States and South Korea in a sea
of flames, defends its nuclear programme as a "treasured sword"
to counter what it sees as U.S.-led hostility.
And there was now "tremendous technological motivation" to
conduct a nuclear test as it races to perfect the technology to
miniaturise warheads, a South Korean nuclear expert said.
"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 miniaturisation was
"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."
David Albright of the Institute for Science and
International Security based in Washington, cited the low yields
of the North's previous nuclear tests as consistent with the
type of yield to be expected from a crude miniaturised warhead.
"North Korea is well aware of Pakistan's and Iran's work on
miniaturising nuclear warheads for (their) missiles, which
originally were copies of the Rodong missile," he said.
"North Korea would have likely made the same judgment as the
two countries about the importance of starting early to develop
a nuclear warhead for its missiles."
Ballistic missile launches are banned under U.N. Security
Council resolutions. The council expanded sanctions after
Pyongyang's February 2013 nuclear test, its third since 2006.
The sanctions target the missile and nuclear programmes and
ban the export of luxury goods to the country, but they cannot
seriously damage trade in a country that does little trade with
the rest of the world.
For North Korea at present, what was likely more at stake
was winning "the political poker game where risks and vague
possibilities are seen as matter-of-fact situations", said
Markus Schiller of Schmucker Technologie in Germany.
For a nuclear missile to reach its target with precision and
undamaged from the stress of launch and re-entry, everything
must work flawlessly and that could be achieved only through
repeated testing, said Schiller, a missile technology expert.
A mid-range Rodong would still require a flight into space
and return to the atmosphere, bearing the full stress of the
re-entry of peak loads of almost 20 times the force of gravity
for a few seconds, he said.
"The big question is whether this warhead would still
function after re-entry," he said. "My current guess is rather
no than yes."
But putting most of Japan within range of a nuclear-tipped
ballistic missile will be sobering for the world's third-largest
economy and its ally, the United States.
"If you can take Tokyo hostage with nuclear weapons, you can
do a lot of things," said Narushige Michishita, a defence expert
formerly involved in Japan's security policy.
(Additional reporting by James Pearson in Seoul, Megha
Rajagopalan in Beijing, Fredrik Dahl in Vienna, David Alexander
and David Brunnstrom in Washington and Timothy Kelly in Tokyo;
Editing by Nick Macfie)