According to reports from the Korean peninsula, construction is already underway on a new diesel-electric ballistic missile submarine Kim Jong Un hopes will ferry his newly developed nuclear missiles closer to their intended targets, marking yet another significant increase the threat posed by North Korea’s nuclear weapons program.

Once complete, the new sub will be significantly smaller than U.S. Ohio class ballistic missile submarines, with an estimated displacement of around 2,000 tons and a beam (or width) of around 36 feet.  For comparison, the USS Michigan, a Ohio-class sub commissioned as far back as 1982, has a displacement of nearly 17,000 tons.  Of course, the size difference isn’t the only thing separating American ballistic missile submarines from North Korea’s new endeavor – Kim’s new sub will undoubtedly be generations behind in terms of technology, making it far easier to locate and track than American or near-peer competitors.

That doesn’t mean the new submarine being built in North Korea’s shipyard doesn’t pose a threat, however.  The ocean is an awfully big place, and a few subs equipped with nuclear tipped missiles could wreak havoc on American allies and military installations throughout the Pacific.  Despite North Korea’s efforts to establish their long-range ballistic missile platforms, firing from a submerged vessel that’s closer to a potential target not only increases chances for success, but dramatically decreases the window for intercepting an offensive launch.

This new platform is likely intended to be the successor to North Korea’s single (similarly sized) Gorae-class submarine, which has never entered operational use, but is technically capable of launching KN11/Pukguksong-1 submarine-launched ballistic missiles (SLBM).  It has been rumored that their Gorae sub (which translates to “Whale”) received a light refit earlier this year, including a new launch tube that may be intended to accommodate larger missile platforms.  North Korea has hinted at the development of a new SLBM in recent months, and experts believe it may be a solid fueled platform Kim’s regime has dubbed the Pukguksong-3, though there’s been no confirmation that the North Korean propaganda photos indicating its development are actually reflective of reality, rather than bravado.