Russia possesses the world’s largest nuclear arsenal, a position it is leveraging alongside an expanding set of strategic capabilities, according to a May 1 report by the Congressional Research Service and U.S. Naval Institute.
The report said Pentagon’s 2026 National Defense Strategy assesses that Moscow maintains the biggest stockpile globally and continues to modernize and diversify its forces, including nuclear delivery systems and supporting cyber, space and undersea capabilities.
According to cited 2026 estimates by the Bulletin of Atomic Scientists, both Russia and the United States have around 1,770 deployed nuclear warheads. However, Russia has a few hundred more total warheads and about ten times more tactical, or non-strategic, nuclear weapons, usually referring to shorter range for a battlefield rather than long-range for large-scale strikes.
Since its 2022 invasion of Ukraine, Russian President Vladimir Putin has repeatedly invoked nuclear signaling to deter Western involvement, while also moving nonstrategic nuclear weapons into Belarus, according to the report.
The finding reinforces long-standing estimates that Russia holds a larger total inventory of nuclear warheads than the United States, with both countries still accounting for the vast majority, around 90%, of the world’s nuclear weapons.
The report comes as the last remaining bilateral arms control framework, the 2010 New Strategic Arms Reduction (New START) Treaty, expired in February without a replacement, raising concerns that both Washington and Moscow could expand deployed forces beyond previous limits.
New START limited each country to 1,550 deployed nuclear warheads, 700 deployed missiles and bombers, and 800 non-deployed launchers and bombers. Defense analysts believe the expiration of New START may lead to a new nuclear arms race, especially as Russia backed out of on-site treaty verification inspections in 2023 amid the Joe Biden administration’s support of Ukraine’s efforts to turn back the Russian invasion.
Absent those constraints, the report said the U.S. and Russia could rapidly upload additional warheads onto existing delivery systems or field new ones, accelerating a renewed arms competition and increasing strategic instability.
The Pentagon assessment underscores that Russia’s nuclear posture—paired with its modernization efforts and willingness to integrate nuclear signaling into conventional conflicts—remains central to U.S. defense planning and deterrence strategy.