The United States has once again focused on alleged nuclear tests by China in the Lop Nor desert, northeast of the Asian giant. On Tuesday, a senior State Department official presented new seismic data to reinforce the accusation that Beijing may have conducted a low-yield nuclear test in June 2020, despite proclaiming strict adherence to the spirit of the Comprehensive Nuclear-Test-Ban Treaty.
According to Washington, a monitoring station in Kazakhstan recorded a magnitude 2.75 event on June 22, 2020. Christopher Yeaw, Deputy Secretary of State, stated that the U.S. "has knowledge" that China conducted a nuclear explosion on that day and placed the probable epicenter in the vicinity of Lop Nor, where Beijing detonated its first atomic bomb in 1964 and its first hydrogen bomb just 32 months later, in a rapid race to close the strategic gap with the U.S. and the Soviet Union.
The accusation comes at a complex moment of legal vacuum following the expiration of the New START treaty, which for over a decade limited the strategic arsenals of Washington and Moscow. With this weakened framework, the Donald Trump administration sought to pressure Beijing to sit at a trilateral table with Russia, even though the Chinese arsenal - although rapidly expanding - remains significantly smaller than that of the other two nuclear powers.
According to the Stockholm International Peace Research Institute (SIPRI), in 2024 China had around 600 nuclear warheads, compared to over 3,700 for the United States and 4,300 for Russia. This figure marks a significant increase: in 2012, when Xi Jinping came to power, China had only 240 warheads. If current trends continue, the Asian country could reach 1,000 warheads or more by 2030, according to Pentagon estimates, which include satellite image analysis indicating the construction of new silos for intercontinental ballistic missiles.
China has recently denied conducting new nuclear tests. Chinese spokespersons claim that their country respects the international moratorium associated with the Comprehensive Nuclear-Test-Ban Treaty (CTBT), signed in 1996 but still not in force due to lack of key ratifications. Beijing signed the treaty but has never formally ratified it, similar to Washington. However, both maintain that they comply with its provisions in practice.
Between 1964 and 1996, China conducted 45 nuclear tests, with the last one precisely the year the CTBT was opened for signature. The treaty prohibits any nuclear explosion with energy yield but allows subcritical tests and experiments with fissile material that do not produce self-sustained nuclear reactions. Experts point out that this dividing line is very thin and, above all, difficult to verify when it comes to small explosions.
However, U.S. officials have insisted that China may be using techniques to mask the seismic signature of its nuclear tests, conducting detonations in pre-excavated underground cavities to dampen the shockwave.