The Pentagon’s Joint Staff is conducting an urgent threat assessment of North Korea’s new road-mobile missile and the danger it poses to the United States.
The classified assessment is being done for Gen. Martin Dempsey, chairman of the Joint Chiefs of Staff, on an expedited basis, said defense officials familiar with the effort.
“This is an expedited examination of the North Korean ICBM threat specifically for the chairman,” one official said.
A Joint Staff spokesman declined to comment on the North Korean ICBM assessment.
Disclosure of the urgent threat assessment from nuclear-armed North Korea comes as President Barack Obama is expected to announce Tuesday night that he plans to cut an additional one-third of the warheads from the U.S. nuclear arsenal.
The Pentagon plans to cut its nuclear warheads to 1,550 warheads under the 2010 New START arms treaty with Russia. An additional cut of a third of those warheads would bring the U.S. warhead arsenal to around 1,000.
Nuclear deterrence specialists have said cutting warheads below New START levels would undermine strategic deterrence and spur nations that rely on U.S. nuclear weapons to seek their own nuclear arms.
The Joint Staff assessment was ordered following recent intelligence reports indicating development work on the North Korean KN-08 mobile ICBM is nearing completion. Several KN-08s were spotted moving around North Korea in January.
The assessment is also expected to address whether North Korea will share the mobile ICBM technology with Iran. North Korea in the past has sold and shared its ballistic missile technology with Tehran, including the medium-range Nodong that Iran calls the Shahab-3.
The study is expected to impact the Obama administration’s plans for U.S. missile defenses.
Currently, the Pentagon operates a limited missile defense system designed to counter a small number of long-range North Korean missiles with 30 interceptors based in Alaska and California.
The Obama administration opposes expansion of long-range ground based interceptors in favor of its European-based missile defenses that call for developing an enhanced version of the Navy SM-3 interceptor that can knock out ICBMs.
A recent Government Accountability Office report on missile defense found problems with the Pentagon’s plan to deploy the SM-3 Block IIB for use against ICBMs by 2020.
Some officials said there were indications North Korea could test a KN-08 or the medium-range Musudan around the time of its nuclear test.
U.S. intelligence agencies are closely watching North Korea for signs of a missile test, officials said.
The Joint Staff study was underway prior to North Korea’s third underground nuclear test Tuesday, which Pyongyang claimed was a major step toward developing a small nuclear warhead for its missiles.
The KN-08 ICBM was first disclosed in April 2012 during a military parade.
Officials said it represents a new level of threat to the United States because although it has yet to be flight-tested, U.S. intelligence agencies believe it will be able to range Alaska, Hawaii, and the western United States.
North Korea’s other long-range missile is the static-launched Taepodong-2 ICBM. Pyongyang also has developed an intermediate-range nuclear missile called the Musudan, based on a Soviet-designed ICBM.
U.S. officials regard the Taepodong-2 as vulnerable to preemptive attack because of the relatively long times required for set up and launch.
The U.S. military regards road-mobile ICBMs like the KN-08 as a much greater threat because the missiles can be moved easily, hidden in garages, and launched with little or no warning.
A 2010 U.S. intelligence assessment of North Korea’s missile programs, disclosed in a leaked State Department cable, revealed that North Korea was developing ICBMs in three paths, including using the Taeopodong-2; further developing its intermediate-range missile; and “use the very large launch facility that is being constructed on the west coast of North Korea to launch a very large missile.”
U.S. officials said the new launch site is believed to be where the new KN-08 is being developed.
According to the 2010 cable, the United States said the new North Korean missile facility is “of concern.”
“It does not simply replicate other sites,” the cable said. “This facility is much larger than the Taepodong launch facility. This is not to say there is evidence of a new missile system larger than the Taepodong-2 being developed, but it suggests the possibility.”
A second cable from 2009 said North Korea’s new Musudan medium-range missile is a solid-fueled, road mobile system. The cable said “the pursuit of longer-range systems remains a DRPK priority.” DPRK is short for Democratic People’s Republic of Korea, North Korea’s formal name.
“North Korea's next goal may be to develop a mobile ICBM that would be capable of threatening targets around the world, without requiring the lengthy—and potentially vulnerable—launch preparation time required by the TD-2,” the cable said.
Missile and nuclear specialists outside the government on Tuesday debated whether North Korea’s boast about having a miniaturized nuclear weapon that could fit on a missile is accurate.
David Albright, a nuclear specialist with the Institute for Science and International Security (ISIS), said if the miniaturized nuclear device is confirmed, “it should not be a surprise.”
“It should not come as a surprise to the international community that North Korea may now have the capability to explode a miniaturized nuclear device,” Albright said in an analysis coauthored with Andrea Stricker. “ISIS and key members of the U.S. intelligence community have assessed for some time that North Korea likely has the capability to miniaturize a nuclear weapon for its 800 mile range Nodong missile.”
Albright and Stricker said more information is needed to make a better assessment, but the organization believes North Korea lacks the ability to deploy a nuclear warhead on an ICBM.
Former CIA officer Fred Fleitz, who once worked for the agency’s Weapons Intelligence Non-Proliferation and Arms Control Center, said he is skeptical of North Korea’s claim to have miniaturized a warhead.
“The test may have been a step toward miniturization and may have been slightly smaller than past devices,” said Fleitz, now with the private Langley Intelligence Group Network (LIGNET). “But the North Koreans are a long way from building a small warhead that could fit on an ICBM capable of hitting the United States.”
“North Korea’s third nuclear test, particularly if it was successful in testing a ‘miniaturized’ device, may represent a significant upgrade in its nuclear weapons program,” a LIGNET assessment stated. “Miniaturization is critical to mate a nuclear warhead to a delivery system such as a ballistic missile.”
“However, confirming whether North Korea actually tested a miniaturized nuclear device is impossible unless it allows outside experts to examine one of these devices or their nuclear plans,” the assessment said. “Going from a crude nuclear device, which would be large and heavy, to a miniaturized one is a huge technical leap, requiring major advances in nuclear science and metallurgy.”