* North Korea could conduct new nuclear test soon - Hecker
* More needed to make weapon small enough for missile
* Pyongyang's "bark much greater than its bite"
(Adds quotes on North Korea's capabilities, paras 3, 5, 6, 17)
By Fredrik Dahl
VIENNA, April 18 North Korea would need to carry
out at least one more nuclear test in order to develop a nuclear
missile, a prominent U.S. scientist who has often visited the
isolated Asian state said on Thursday.
Stanford University's Siegfried Hecker, who in 2010 was
shown a previously undetected uranium enrichment facility in
North Korea, said he believed it could conduct its fourth such
explosion in weeks or months.
"I still don't think they have enough nuclear-testing
experience," Hecker told a seminar of the Vienna Center for
Disarmament and Non-Proliferation.
The North has threatened nuclear attacks on the United
States, South Korea and Japan after new United Nations sanctions
were imposed in response to its latest nuclear arms test in
February, the third since 2006.
Hecker, who is believed to have been the last Westerner to
visit North Korea's Yongbyon nuclear complex, said the situation
was serious but Pyongyang did not have the capability to carry
out most of its threats.
"The bark is much greater than the bite but you still have
to worry about it," he said.
Pyongyang's nuclear arms still are probably primitive and it
would likely need several more tests to be able to make one
small enough for a missile and have "sufficient confidence that
you can put a nuclear weapon on a warhead", Hecker said
The most important and serious short-range threat could
instead be delivery of a nuclear bomb by other means than a
missile, for example on a boat or even in a car or van.
"That would be the simplest delivery mechanism. However, it
is very difficult to pull that off," he added. "In the shorter
term, most likely a boat would be the most serious threat."
Missile launches and nuclear tests by North Korea are both
banned under U.N. Security Council resolutions.
North Korea deems its nuclear arms a "treasured sword" and
has vowed never to give them up.
PENTAGON SPY AGENCY REPORT
Signalling a possible end to weeks of hostility on the
Korean peninsula, however, North Korea on Thursday offered the
United States and South Korea a list of conditions for talks,
including the lifting of the U.N. sanctions.
The United States has offered talks, but on the
pre-condition that they lead to North Korea abandoning its
nuclear weapons ambitions.
Hecker made clear he did not agree with a Pentagon spy
agency report that triggered alarm last week that North Korea
might be able to deliver a nuclear-tipped missile at a time of
heightened tensions in Asia over Pyongyang's threats of war.
The evaluation from the Defense Intelligence Agency (DIA),
produced in March and revealed at a congressional hearing,
concluded that North Korea likely has nuclear bombs that could
be delivered by missiles.
The Obama administration has played down the DIA report.
"They (North Korea) are very determined people," Hecker
"They can probably develop an ICBM (Intercontinental
Ballistic Missile), they can probably miniaturise nuclear
weapons. But they need lots of missile tests and they need more
North Korea occasionally lets experts like Hecker into the
country, most likely to persuade them that it is not bluffing
over its nuclear capabilities, U.N. diplomats and officials say.
(Editing by Michael Roddy)