All nine nuclear-armed states have modernized and expanded their arsenals amid growing global tensions, according to a report by a respected arms research institute released on Monday.
The report by the Stockholm International Peace Research Institute (SIPRI) found a broad trend of nuclear build-up across all nine states.
"‘The evidence is growing that the nuclear weapon states are sidelining, and even walking away from, their disarmament commitments and are instead flexing their nuclear muscles," SIPRI researcher Hans Kristensen said in a statement.
"By reaching for nuclear solutions, states are creating new risks and fuelling arms-race dynamics," he said.
Moscow has alluded to its nuclear potential during its war against Ukraine in order to deter Western countries from supporting Ukraine.
Russia and the US together hold around 83% of all stored nuclear warheads, according to SIPRI estimates. After the end of the Cold War, the two countries had gradually dismantled decommissioned warheads, causing the global stockpile of nuclear weapons to fall steadily.
This trend is likely to reverse in the coming years as the pace of disarmament slows while the deployment of new nuclear weapons increases, the SIPRI report said.
According to the researchers' estimates, the nine nuclear-armed powers - the US, Russia, the United Kingdom, France, China, India, Pakistan, North Korea and Israel - possessed 12,187 nuclear warheads as of January 2026.
Around 9,745 of these were held in military stockpiles for potential use, the researchers said.
More than in the previous year - an estimated 4,012 - were deployed on missiles and aircraft. Between 2,100 and 2,200 were kept on ballistic missiles at the highest level of readiness, with almost all of these belonging to Russia or the US and, to a lesser extent, the UK and France.
Following the departure of the UK from the EU, France is the only nuclear power within the bloc.
