North Korea is continuing to build its long-range missile capabilities, possibly including a submarine-launched ballistic missile, a ranking U.S. defense official said Wednesday.
"We don't know what the risk is because we know that North Korea is trying to increase the size of its ICBM capabilities, maybe even move to a submarine launched ballistic missile, but we don't know the extent of that," said Rob Soofer, deputy assistant secretary of defense for nuclear and missile defense policy.
Soofer's remark comes months after the South Korean Defense Ministry said the North may showcase a new intercontinental ballistic missile or a submarine-launched ballistic missile in a massive military parade to mark the 75th anniversary of the founding of its ruling Workers' Party on Oct. 10.
North Korea has kept a moratorium on nuclear and ballistic missile testing since late 2017 when it staged its sixth and latest nuclear test, a few months before leader Kim Jong-un held a historic summit with U.S. President Donald Trump.
The communist state, however, is suspected of having maintained clandestine programs to further its nuclear and missile capabilities.
Soofer, speaking in a webinar hosted by U.S.-based Mitchell Institute for Aerospace Studies, said the U.S. is enhancing its missile defense capabilities in response, partly with the standard missile-3 (SM-3) block IIA, which he said may be deployed in the near future.
"We will conduct a test before the end of this calendar year, and if it works, then figure out some way to integrate into our defense," he said.
"And if it does work now, we have the capability to address the North Korean threat," added Soofer.
The so-called U.S. missile shield has partly been blamed for triggering an arms race, especially with nuclear states such as China and Russia, but the defense official insisted the new SM-3 interceptors will pose no threat to such countries, given their small number and the fact that they will be "spread throughout the region."
When asked about ongoing discussions on the benefits of the U.S. pledging to "no first use" of nuclear weapons, the defense department official said the U.S. should not give its adversaries and those of its allies the wrong idea.
"The problem with a no first use pledge is that it lowers the risk to adversaries who are contemplating a conventional attack against our allies. They may think ... if they attack us with conventional forces, overwhelming conventional forces, say, in the Korean Peninsula, that they could push us back," he told the online seminar.
South Korea has been and still is under the U.S. nuclear umbrella, under which the U.S. offers nuclear deterrence against threats from other nuclear states against South Korea, a non-nuclear state.
A U.S. expert on North Korea later claimed the North may unveil its first-ever solid-fueled ICBM at the upcoming Oct. 10 parade, citing White House and U.S. intelligence officials.
"That seems to be the most likely of scenarios based on their history, and it's what we are expecting, but, of course, we are hoping to be proven wrong," Harry Kazianis wrote in an article published by U.S. bimonthly magazine National Interest.
A solid-fueled missile would provide much more mobility, Kazianis said, adding that North Korea's current-long range ICBMs ― the Hwasong-14 and Hwasong-15 ― use liquid-based fuel that requires longer preparation times and cannot be left in a fueled state due to the corrosive nature of the chemicals used.
"Solid-fueled missiles carry the advantage of being able to stay in a fueled and ready-to-strike state. As a result, they are much more reliable and can be launched faster," he said.
In December 2019, North Korea staged what it called a "very important test" followed by "another crucial test," both at its satellite launch site, known as the Dongchang-ri site.
Kazianis noted that many suspect the tests to have been based on solid-fuel technology.
Officials from Seoul and Washington have said the tests appeared to have involved liquid-fuel engines for multi-stage rockets.