North Korea claims to have made progress on miniaturized nuclear devices. Some experts credit that claim, but much of what North Korea can or can't do remains unknown.
Following its Feb. 12 nuclear test, Pyongyang boasted that it had detonated a “miniaturized and lighter nuclear device." Some US experts interpreted this to mean that North Korea is claiming to have developed a weapon that would fit on a Nodong medium-range rocket or, perhaps, even the untested, longer-range KN-08. This would threaten South Korea and perhaps Japan, but not the US mainland itself.
The public US government position is that it does not know how far down the road toward miniaturized nuclear devices North Korea has progressed. In 2005, the director of the Defense Intelligence Agency told a congressional hearing that North Korea had the capability to arm a missile with a plutonium-based nuclear device, but Pentagon officials later backed away from that conclusion, according to a 2013 Congressional Research Service report on technical issues related to North Korea’s nuclear weapons.
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