China is accelerating its nuclear buildup over rising fears of U.S. conflict

China has accelerated an expansion of its nuclear arsenal because of a change in its assessment of the threat posed by the U.S., people with knowledge of the Chinese leadership’s thinking say, shedding new light on a buildup that is raising tension between the two countries.

The Chinese nuclear effort long predates Russia’s invasion of Ukraine, but the U.S.’s wariness about getting directly involved in the war there has likely reinforced Beijing’s decision to put greater emphasis on developing nuclear weapons as a deterrent, some of these people say. Chinese leaders see a stronger nuclear arsenal as a way to deter the U.S. from getting directly involved in a potential conflict over Taiwan.

Among recent developments, work has accelerated this year on more than 100 suspected missile silos in China’s remote western region that could be used to house nuclear-tipped missiles capable of reaching the U.S., according to analysts that study satellite images of the area.

American leaders have said the thinking behind China’s nuclear advance is unclear. Independent security analysts who study nuclear proliferation say they are also in the dark about what is driving Beijing after exchanges between Chinese officials and analysts mostly dried up in the past few years.