South Korea’s new KTSSM bunker-buster missile enhances conventional strike capabilities while quietly positioning the country for a potential independent nuclear deterrent.
The missile’s deployment signifies a broader strategic change that could potentially blur the boundaries between conventional and nuclear postures.
This month, Yonhap News Agency reported that South Korea has fielded the Korean Tactical Surface-to-Surface Missile (KTSSM), a domestically developed precision-strike weapon designed to neutralize North Korea’s underground artillery sites.
Dubbed “Ure” (Thunder), the KTSSM can conduct rapid, simultaneous precision strikes, targeting North Korea’s long-range artillery, much of which is positioned within striking distance of Seoul.
With a range of 180 kilometers, the missile enhances South Korea’s deterrence posture amid escalating tensions. The South Korean Joint Chiefs of Staff (JCS) emphasized that the deployment provides the military with an “overwhelming” capability to destroy enemy positions in a contingency.
The KTSSM was first developed following North Korea’s November 2010 bombardment of Yeonpyeong Island. Global Security notes that KTSSM is an affordable tactical ballistic system similar to the US Army’s Tactical Missile System (ATACMS), though it offers improved accuracy at the expense of a shorter range.
There are two variants: KTSSM-1, which is intended to target North Korea’s M1978/M1989 Koksan 170-mm howitzers and M1985/M1991 240-mm multiple rocket launchers (MRL), and KTSSM-2, a self-propelled unit designed to strike North Korea’s KN-09 300-mm MRLs and KN-02 short-range ballistic missiles (SRBM).
The Koksan’s range with conventional shells is 40 kilometers and 60 kilometers with rocket-assisted projectiles, while North Korea’s 240-millimeter MRLs have a similar range. The KN-09 has an estimated range of 200 kilometers and the KN-02 falls within the 120-170 kilometer range.
KTSSM Block 1 features a thermal penetrating warhead, while Block 2 employs a unitary high-explosive warhead. South Korea deploys the KTSSM at the corps level, whereas its Army Missile Command operates the Hyunmoo and ATACMS systems.
North Korea’s hardened artillery sites (HARTS) remain a significant threat. Kyle Mizokami, in a January 2021 article for The National Interest (TNI), states that North Korea has between 200 and 500 HARTS positioned in the mountains north of the Demilitarized Zone (DMZ).
These artillery pieces can fire and retreat into the mountains to reload. North Korea intends to use these sites to either support a potential invasion or as a means of bombardment against Seoul. It can also use its artillery threat as a means of coercion against the US and South Korea without relying on chemical or nuclear weapons.
An August 2020 RAND Corporation report estimates that North Korea possesses around 6,000 rocket and tube artillery pieces capable of striking significant South Korean population centers with high-explosive ammunition. Even a brief, targeted barrage could inflict catastrophic damage.
RAND warns that if these artillery units fired for an hour, fatalities could reach 100,000, while strikes on industrial facilities could devastate South Korea’s economy. The report stresses that the rapid onset of destruction would make it difficult for the US and South Korea to prevent mass casualties or protect civilian populations.
While these assessments underscore the scale of the threat, other experts caution against overstating North Korea’s artillery capabilities.
In a November 2024 Modern Warfare Institute (MWI) article, Ju Hyung Kim argues that North Korea’s artillery, though significant, may not be as formidable as often portrayed. He notes that North Korea likely possesses only about 100 170-millimeter self-propelled guns and 200 240-millimeter MRLs that could reach Seoul.
Kim also highlights the poor accuracy and high dud rate of North Korea’s artillery. During the 2010 Yeonpyeong bombardment, North Korea fired 400 rounds, yet only 80 reached their targets, while 320 fell into the sea. Of the 80 that hit their targets, 20 failed to detonate.
From that, Kim estimates that in a full-scale attack on Seoul, North Korea’s 170-millimeter guns could fire 100 shells, while its 240-millimeter MRLs could fire 4,400 rockets, but only 48 shells and 1,840 rockets would reach the city.
Given Seoul’s vast urban sprawl, the prevalence of reinforced concrete structures and the high dud rate of North Korean munitions, he argues that the damage inflicted by such an attack would be considerably lower than worst-case projections suggest.
While North Korea’s nuclear arsenal dominates discussions about deterrence, South Korea’s investment in conventional weapons such as the KTSSM demonstrates the continued relevance of non-nuclear deterrence.
In a 2019 Federation of American Scientists (FAS) report, Adam Mount critiques South Korea’s reliance on the US nuclear umbrella, arguing that it is an inadequate response to North Korea’s limited acts of aggression and risks unnecessary escalation.
He contends that conventional responses are preferable due to nuclear escalation’s operational, economic, political, human and normative costs. Mount further notes that relying on nuclear weapons for deterrence imposes strategic constraints while offering little practical leverage.
Politically, he contends that South Korea’s reliance on US extended deterrence presents a dilemma; the US is unlikely to forward-deploy nuclear weapons to the Korean Peninsula, and even if it did, their operational utility would be limited. Further, South Korea’s strategic calculations could be complicated by the potential for the US to use nuclear weapons against the former’s wishes.
Given these constraints, South Korea’s development of the KTSSM aligns with its broader conventional counterforce and countervalue strategy.
In a 2021 International Security journal article, Ian Bowers and Henrik Hiim argue that South Korea’s pursuit of these capabilities reflects a long-term strategy of hedging against potential US abandonment while reinforcing its nuclear latency.
North Korea’s intercontinental ballistic missiles (ICBM) capable of striking the US mainland amplifies the risk that the US could dilute its nuclear-extended deterrence commitments to South Korea.
This strategic uncertainty incentivizes South Korea to enhance its independent deterrence capabilities, ensuring that it retains the ability to preemptively neutralize North Korea’s nuclear arsenal and leadership if necessary.
In the short term, South Korea’s emphasis on conventional deterrence enables it to credibly threaten North Korean military assets without escalating to nuclear brinkmanship.
Over the long term, however, developments such as the KTSSM provide South Korea with a technological foundation for rapid nuclear weaponization should the security environment necessitate such a shift.
Bowers and Hiim say South Korea’s nuclear hedging strategy is based on dual-use missile systems. This means that South Korea is deliberately building up capabilities that could be used for nuclear deterrence, if necessary, while avoiding the immediate risks and political fallout of pursuing nuclear weapons.
The KTSSM’s deployment highlights South Korea’s evolving security calculus. While still under the US nuclear umbrella, South Korea’s investment in advanced conventional strike systems signals a growing desire for strategic autonomy.
The missile serves an immediate tactical purpose—countering North Korea’s artillery threat—but its broader implications extend into nuclear strategy.
