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Region of Concern: North Korea; South Korea; Japan; China; Russia; USA

Written By Tejas Vaidya; Edited by Elena Alice Rossetti

Date: September 8, 2023

Map of Sea of Japan[1]

Event: On September 8, state media announced North Korea had launched its first operational “tactical nuclear attack submarine,” Hero Kim Kun Ok.[2] The submarine is deployed in the Sea of Japan.[3] Analysts suggest it is a Soviet-era Romeo-class submarine, equipped with 10 launch tube hatches, that are most likely capable of launching ballistic and cruise missiles.[4] North Korea had previously test-fired several submarine-launched ballistic missiles (SLBMs) and cruise missiles (SLCMs),[5] but it is unclear whether it has successfully developed the miniaturized nuclear warheads.[6] Analysts claim the submarine is vulnerable to anti-submarine warfare and “may not survive as long during a war” as it is noisy, slow, and has a limited attack range.[7] North Korea plans to modify existing submarines into nuclear-armed vessels.[8] The Korean People's Army Naval Force (KPANF) has about 470 surface vessels, 70 submarines, including Romeo-class vessels of Soviet-era design, and midget submarines.[9] North Korea is prioritizing developing its naval forces to counter the USA and its Asian allies.[10]

Significance: A North Korean operational tactical nuclear submarine will almost certainly escalate regional tensions as it poses a direct security threat to South Korea, Japan, and the USA. Regional powers will very likely bolster their defense capabilities, increase defense spending, and pursue military developments, which will very likely trigger an arms race in the Indo-Pacific. The USA will very likely respond to the North Korean threat reaffirming its commitment to regional security by increasing naval deployments, joint exercises with allies, and intelligence-sharing efforts. United Nations Command (UNC), which oversees the armistice on the Korean Peninsula, will very likely intensify its monitoring and surveillance activities along the Demilitarized Zone (DMZ) and the Northern Limit Line (NLL) to track North Korean military movements. China, as North Korea's closest ally and a regional power, will likely come under increased scrutiny for its role in enabling North Korea's nuclear and missile programs. This will likely strain China's relations with the US and other Indo-Pacific nations and lead to calls for a Chinese intervention in controlling North Korea's actions. Heightened regional tensions, a hostile security environment, and increased militarisation will almost certainly have an adverse impact on maritime trade compromising energy security, disrupt supply chains, and suspend resource exploration. Diplomatic efforts to denuclearize North Korea will very likely face setbacks, and thus undermine global non-proliferation efforts.

Recommendations: CTG recommends regional nations reevaluate their defense strategies in response to North Korean enhanced maritime capabilities and maintain a robust naval presence. The regional defense mechanisms need to prioritize equipping modern anti-submarine warfare (ASW) assets and develop the ability to detect, track, and respond to North Korean submarines effectively. Global intelligence and security agencies should closely monitor North Korean nuclear testing and other military technological advancements, and weapon procurement and export with Russia and China. Regional countries should strengthen their alliances and partnerships as a strong alliance network provides a collective security umbrella and enhances deterrence. South Korea and its allies, through diplomatic channels, should warn North Korea of the consequences of potential aggressive submarine actions. Regional powers should pursue diplomatic dialogue with China and Russia, and encourage them to support and enforce the United Nations Security Council (UNSC) resolutions related to North Korea's nuclear program, including sanctions and non-proliferation measures. Regional nations and their allies should put economic and political pressure on North Korea through sanctions and diplomatic isolation.


[1]Map of Sea of Japan” by Tejas Vaidya via Google Earth

[2] North Korea unveils first tactical, nuclear-armed submarine, Reuters, September 2023,

[3]North Korea launches new tactical nuclear attack submarine, Channel NewsAsia, September 2023

[4]North Korea unveils first tactical, nuclear-armed submarine, Reuters, September 2023,

[5] North Korea launches new tactical nuclear attack submarine, Channel NewsAsia, September 2023,

[6] Ibid

[7] North Korea unveils first tactical, nuclear-armed submarine, Reuters, September 2023,

[8] Ibid

[9] Why is North Korea growing its navy with submarines and nuclear drones?, Reuters, September 2023,



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