South Korea’s President Lee Jae-myung has said North Korea is in the “final stage” of developing an intercontinental ballistic missile (ICBM) capable of delivering a nuclear warhead to the United States, with only atmospheric re-entry technology left to master.
Speaking in New York on Thursday, 25 September, during a visit for the United Nations General Assembly, Lee said Pyongyang’s long-range missile work was continuing “for negotiations with the U.S. or for their own regime,” and warned that re-entry issues were “likely to be resolved soon.”
Lee’s remarks follow a series of signals that North Korea intends to consolidate advances in solid-fuel, road-mobile ICBMs. In late 2024, Pyongyang announced it had flight-tested its largest missile to date, the Hwasong-19, on a highly lofted trajectory into space. External analysts have said such systems could place the entire U.S. mainland within range, though questions remain about the reliability of guidance and the survivability of a nuclear payload during high-heat re-entry at intercontinental velocities.
Addressing investors at the New York Stock Exchange on Thursday, Lee linked the security outlook to South Korea’s economic objectives, saying his administration intends to reduce peninsula-related risk to attract capital and support growth. His New York programme this week has also included talks with U.S. lawmakers on trade and tariff issues, with the president noting market sensitivity to the negotiations.
Lee said North Korea appears to have accumulated enough nuclear weapons to ensure regime survival and cautioned that additional production poses a proliferation risk if warheads or related technology are transferred overseas. He called for a negotiated cap and reduction in the medium term, with denuclearisation pursued over a longer horizon.
On diplomacy, Lee reiterated his view that U.S. President Donald Trump is the only viable negotiating counterpart for Pyongyang at present. Trump said on 25 August that he wished to meet North Korean leader Kim Jong-un “this year,” though no date has been announced. Lee has proposed inter-Korean talks since taking office in June, but Pyongyang has rejected Seoul’s overtures.
Lee’s assessment of the ICBM timeline centres on the re-entry phase—the point at which a missile’s payload must survive extreme thermal and mechanical stress as it descends through the atmosphere and still detonate at the intended target. North Korea has demonstrated high-apogee flights that test structural loads and engine performance but provide limited proof of re-entry integrity at full-range speeds. Without a reliable heat-shield and guidance package, an ICBM cannot deliver a warhead accurately to intercontinental distances. That gap, Lee suggested, may be narrowing.
The Hwasong-19—described by North Korean media as a solid-fuel, multi-stage system and an evolution of the Hwasong-18—represents Pyongyang’s attempt to field a quicker-to-launch, harder-to-detect deterrent. Solid propellant eliminates lengthy fuelling on exposed launch pads, complicating allied early-warning and strike options. Analysts caution, however, that even if range is technically sufficient, integrating reliable re-entry vehicles and, potentially, multiple independently targetable re-entry vehicles (MIRVs) is a separate engineering challenge.
The strategic context is fluid. Reuters reported this week that Lee has been pressing economic arguments in parallel with security engagement during his U.S. trip, amid separate debates over tariffs and investment balances with Washington. Meanwhile, North Korea’s foreign minister is due to visit China from 27–30 September, underscoring Pyongyang’s reliance on Beijing for diplomatic and economic support at a time of continuing weapons development and sanctions pressure.
Lee’s comments come as Seoul seeks to maintain allied pressure while leaving room for talks. The South Korean government has aligned with the United States and Japan on missile defence drills and sanctions enforcement, and has publicly supported renewed U.S.–DPRK contact should conditions allow. Trump’s statement in August indicated interest in another summit-level meeting, though the administration has not detailed a framework for negotiations or potential reciprocal steps. North Korea has said it is open to discussions if Washington abandons demands for prior denuclearisation commitments.
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