North Korea is estimated to possess up to 150 nuclear weapons, with projections suggesting that its arsenal could grow to more than 400 by 2040.
Military cooperation between Pyongyang and Moscow is significantly bolstering North Korea’s military capabilities across multiple domains, including the advancement of strategic missiles and naval modernization. Analysts suggest this shift reflects North Korea’s strategic pivot towards reshaping the global order into a multipolar system, rather than seeking improved relations with South Korea and the United States.
During the 2025 North Korean Military Forum held in Seoul on Wednesday, Lee Sang Kyu, director of the Nuclear Security Research Office at the Korea Institute for Defense Analyses (KIDA), explained that following the 2023 Workers’ Party plenary meeting’s decision to increase nuclear warhead stockpiles exponentially, North Korea has been aggressively expanding its facilities and investments to boost atomic material production.
Lee’s analysis estimates that North Korea currently possesses between 127 and 150 nuclear weapons, including 115-131 uranium-based and 15-19 plutonium-based warheads.
This assessment significantly exceeds foreign estimates from organizations such as the U.S. Congressional Research Service (CRS), Defense Intelligence Agency (DIA), Stockholm International Peace Research Institute (SIPRI), and Japan’s Nagasaki University Center for Nuclear Weapons Abolition (RECNA), which generally place North Korea’s nuclear arsenal at around 50 warheads.
The dramatic increase in estimates reflects North Korea’s expanded uranium enrichment capabilities, as evidenced by Kim Jong Un’s recent unveiling of previously undisclosed nuclear material production facilities.
Lee projects that by 2040, North Korea could amass up to 386 uranium warheads and 43 plutonium warheads, potentially pushing its total nuclear arsenal beyond 400 weapons.
Regarding the nuclear-powered submarine North Korea claimed to be constructing in March, Lee speculates that Russian technology transfer may be involved and estimates the vessel’s displacement at 5,000 to 6,000 tons.
He noted that critical subsystems and equipment, such as reactors and vertical or horizontal launch systems, are likely not yet fully integrated. He further assessed that developing a compact submarine reactor requiring fuel enriched above 20 percent could take over a decade, which may explain North Korea’s strong interest in obtaining this technology from Russia.
Lee emphasized North Korea’s growing focus on integrating nuclear and conventional weapons (CNI) in its military doctrine. This strategy aims to overcome traditional force limitations by combining nuclear capabilities with long-range artillery, multiple rocket launchers, and cyber warfare, and by implementing a mixed-firing approach that simultaneously uses nuclear and conventional missiles.
To counter these developments, Lee proposed establishing a Strategic Deterrence Committee (SDC), a civil-military collaborative body centered around the National Security Office.
In a separate analysis, Jeon Kyung Joo, head of KIDA’s Korea Security Research Office, noted that North Korea is reinforcing its status as a nuclear power by intensifying its deterrence rhetoric, including threats of nuclear retaliation against conventional South Korean attacks.
Jeon pointed out a significant shift in North Korea’s nuclear posture. During the 8th Workers’ Party Congress in 2021, when Pyongyang viewed Seoul as a potential conduit for U.S. negotiations and economic aid, it outlined a five-year defense modernization plan while maintaining a no-first-use nuclear policy. However, this stance has radically changed as North Korea now views South Korea as a hostile state.
Jeon concluded that North Korea is showing growing interest in participating in joint air and naval exercises led by authoritarian states such as China and Russia, and is likely to use the current geopolitical environment to expand its strategic influence beyond the Korean Peninsula.