China has the fastest-growing nuclear arsenal in the world. SIPRI estimates its stockpile at 620 warheads in January 2026, up from about 600 a year earlier, and says China has loaded hundreds of missiles into new silo fields.1 It remains far smaller than the American or Russian arsenals, but it is no longer the minimal deterrent China kept for half a century, and it is the main reason Washington gives for its own build-up.
The silos, acknowledged
Satellite imagery revealed three large silo fields in China's north-west in 2021, with outside estimates of around 320 silos. Beijing never confirmed them. In September a state-media documentary marking the People's Liberation Army's anniversary featured an army engineer describing his work building "houses for missiles", the country's "strategic trump cards", on a tight schedule completed on time. It is the first semi-official acknowledgment.2
Robert Rust, writing in the Bulletin of the Atomic Scientists, reads the timing as a signal: the build-up is presented as securing a second strike that can survive a US first strike and penetrate US missile defences, not as a change of doctrine.3 China continues to state a policy of no first use.2
A missile into the South Pacific
On 6 July China test-fired a submarine-launched ballistic missile some 7,000 km from the South China Sea into open water between Kiribati and Tuvalu, inside the South Pacific Nuclear Free Zone. China did not name the missile. Taiwan's intelligence service said it was a JL-2; other analysts think it was the longer-range JL-3, which could reach most of the continental United States from waters near China.4 The test is a step towards a sea-based deterrent that can stay hidden, the hardest leg of a nuclear force for an adversary to target. Analysts at CSIS argued that it shows the need for a US–China agreement to notify each other of ballistic missile launches, of the kind the US and Russia have had since 1988.5
"Strategic stability", undefined
At their summit in Beijing in May, Donald Trump and Xi Jinping committed to building a relationship of "constructive strategic stability". They met again in Washington in September. Neither meeting defined the term or produced nuclear talks. Analysts note that Beijing reads it as a US commitment not to interfere in China's "core interests", while Washington has paid it little attention.6 The September summit's results were mainly about trade.7
One nuclear-related commitment does exist. The US and China agreed in 2024 that humans, not AI, must control decisions to use nuclear weapons, and the principle was reaffirmed at the review conference of the Non-Proliferation Treaty this year (see Keeping AI out of the launch decision).8
The dilemma
China's build-up and America's are each justified by the other. Beijing cites US missile defence and US conventional strike power; Washington cites the Chinese silos. With no treaty covering China, and China saying it will not join negotiations at this stage, the arsenals can grow in step with nothing to cap them. The modest measures analysts propose, such as launch notification, a missile-defence dialogue, and a shared definition of strategic stability, would not stop that race, but they would make it less likely that a test or an exercise is misread in a crisis.