North Korean leader Kim Jong-un said at the submarine's launch ceremony on Wednesday that submarine 841, named "Hero Kim Kun Ok" after a North Korean historical figure, will be one of North Korea's main "underwater offensive assets of the navy", KCNA reported.
Equipping the fleet with nuclear weapons is an "urgent task". According to North Korea's KCNA news agency, he pledged to transfer more submarines and surface ships equipped with tactical nuclear weapons to the navy.
Analysts say the vessel appears to be a modified Soviet-era Romeo-class submarine that North Korea bought from China in the 1970s and began producing domestically, and they add that its design, which has 10 hatches for launch tubes, indicates that it is most likely armed with ballistic missiles and cruise missiles.
Vann Van Diepen, a former US government weapons expert working on the "38 North" project in Washington, said such weapons would not add much value to the North's more powerful land-based nuclear forces because its submarines would not survive that long in a war.
"Once this thing is fielded, it will be highly vulnerable to allied anti-submarine weapons. So from a military point of view, it doesn't make much sense," he added.
The South Korean military commented that the submarine did not appear ready for normal operations and that there were signs that North Korea was trying to exaggerate its capabilities.
Analysts first noticed signs that at least one new submarine was under construction in 2016, and in 2019 the North's state media published images showing Kim inspecting a previously unseen submarine. It is unclear whether North Korea has finished developing the miniaturized nuclear warheads needed to mount submarine-launched missiles. It was noted that the submarine was about to be launched for trials.