The United States has released new details alleging that China carried out a covert underground nuclear test in 2020.
A senior U.S. State Department official said the suspected test took place on June 22, 2020, at China’s Lop Nur nuclear test site in the Xinjiang region. According to the official, seismic data recorded by a monitoring station in Kazakhstan detected a magnitude 2.75 underground explosion, consistent with a nuclear detonation.
Washington maintains that the event cannot be explained by mining activity or natural earthquakes. ’’There is very little possibility that it is anything but an explosion’’, the official said.
However, the allegation remains contested. The Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO), which operates a global monitoring system for nuclear explosions, confirmed that two small seismic events were detected on that date but stated that the data were insufficient to determine their cause with confidence.
Independent experts have also expressed skepticism, noting that the signals were too weak to conclusively identify as a nuclear test.
U.S. officials suggested that China may have used a technique known as ’’Decoupling’’. It is a technique in which a device is detonated in an underground cavity, weakening seismic waves and making the detection of nuclear activities more difficult.
Beijing Rejects Claims
China has strongly denied conducting any nuclear test, calling the accusations baseless and politically motivated. Beijing maintains that it has observed a voluntary moratorium on nuclear testing since its last acknowledged underground test in 1996.
Russia has likewise rejected the allegations, stating that neither Moscow nor Beijing has conducted secret nuclear tests.
The dispute emerged at a particularly sensitive moment for global nuclear stability – the expiration of New START in February 2026 removed the last restrictions on strategic arsenals and heightened the risk of nuclear weapons expansion.
New START (New Strategic Arms Reduction Treaty) was a bilateral nuclear arms control agreement between the United States and Russia that imposed quantitative limits on deployed strategic nuclear weapons and established verification measures. It was signed in 2010.
Analysts say the ongoing dispute points to the erosion of international norms against nuclear testing and growing mistrust among major powers.
Author: Mariam Simsive
