As the Israel–Iran war escalates and global security tensions mount, the spectre of nuclear conflict has once again moved to the forefront. But beyond the world’s largest stockpiles, it is regional rivalries that are drawing renewed scrutiny. According to the Stockholm International Peace Research Institute’s (SIPRI) Yearbook 2025, India has not only widened its nuclear lead over Pakistan in terms of warhead numbers, but is also making significant technological advances in missile systems and delivery capability.
SIPRI, an independent institute based in Sweden, has tracked global armaments, disarmament, and international security trends since 1966. Its annual yearbook is widely regarded as one of the most credible assessments of the world’s nuclear balance.
So, who’s leading the nuclear race in 2025 and who’s catching up fast? SIPRI’s new data shows how each country is rearming in a more dangerous world.
Russia
Russia remains the world’s leading nuclear power in terms of total warheads. SIPRI estimates it holds roughly 5,880 nuclear weapons, with many deployed on missiles and submarines, and around 2,100 kept on high operational alert, ready to launch at short notice.
Despite these staggering numbers, Russia continues to modernise its nuclear arsenal, aiming to upgrade ageing systems and expand its strike capability. But 2024 saw setbacks, including delays in the Sarmat ICBM, a key next-generation missile, and slower progress across other platforms.
The expected buildup of non-strategic nuclear weapons—typically shorter-range, lower-yield warheads intended for battlefield use—has not yet materialised, despite US intelligence assessments as early as 2020 warning that Russia might expand this category significantly. However, analysts caution that Russia maintains a high level of secrecy around such deployments, making it difficult to confirm their current numbers or locations through open sources.
With the New START treaty—the last remaining US–Russia arms control agreement—set to expire in 2026, and no new deal in sight, Russia is widely expected to rearm empty silos and increase its deployed warheads, especially as tensions with the West remain high. SIPRI suggests this could mark the start of a more unpredictable and unrestrained nuclear posture.
United States
Closely behind, the United States possesses an estimated 5,244 nuclear warheads, according to SIPRI, many of which are deployed on submarines, strategic bombers, and land-based missiles. Like Russia, a significant number of these are maintained on high operational alert, capable of being launched within minutes.
SIPRI notes that the US is in the midst of a comprehensive modernisation programme, involving the replacement of ageing Minuteman III intercontinental ballistic missiles (ICBMs), the construction of new ballistic missile submarines, and the development of next-generation air-launched cruise missiles.
However, the report points out that funding and planning issues in 2024 led to delays and increased costs, raising questions about the programme’s long-term timeline. At the same time, the US is adding new non-strategic (tactical) nuclear weapons to its arsenal—a move SIPRI highlights as potentially destabilising, as such weapons are seen as more likely to be used in a limited conflict.
With China’s nuclear arsenal expanding rapidly, SIPRI warns that internal pressure is building within US defence circles to rearm deactivated launchers and broaden deterrence options—a trend that could accelerate the global arms race.
Source: India Today