Thomas G DiNanno, the US Under Secretary of State for Arms Control and International Security, recently claimed that China carried out a covert nuclear explosive test on June 22, 2020, just a week after the deadly 2020 Galwan clash with neighbouring India.

Speaking at an event in Geneva on February 6, 2026, DiNanno stated that the Asian Giant conducted the nuclear explosive tests, involving yields in the “hundreds of tonnes”, and employed techniques designed to conceal them from international monitoring. “China has used decoupling – a method to decrease the effectiveness of seismic monitoring – to hide its activities from the world,” he stressed, alleging that the June 22, 2020 test was deliberately masked. As expected, DiNanno’s claim has triggered a sensation across the globe.

DiNanno told a Disarmament Conference: “I can reveal that the US Government is aware that China has conducted nuclear explosive tests, including preparing for tests with designated yields in the hundreds of tonnes.” The Under Secretary of State added that the Chinese military “sought to conceal testing by obfuscating the nuclear explosions because it recognised these tests violate test ban commitments.“

DiNanno explained that “decoupling” involves conducting a nuclear explosion in a way that dampens seismic signals, making detection by global monitoring systems quite difficult. Such techniques, if proven, would certainly challenge the effectiveness of international verification regimes designed to enforce nuclear test bans. He also urged the international community to rethink of global arms control frameworks, stressing that the existing treaties no longer reflect current threats. DiNanno made the request soon after Washington DC presented a plan advocating three-way nuclear discussions, involving the US, Russia and China (after New START expired on February 6, 2026). China has already rejected joining such disarmament negotiations “at this stage”.

It may be noted that US President Donald John Trump, too, hinted in 2025 that China conducted a test explosion of a nuclear bomb. However, he did not provide any details. Meanwhile, political analysts are of the opinion that the latest allegations may add strain to US-China relations and inject fresh volatility into global non-proliferation efforts, particularly as arms control agreements face growing uncertainty.

On the night of June 15-16, 2020, at least 20 Indian personnel, including a Colonel, were killed in violent clashes with Chinese troops along the Line of Actual Control (LAC) in Ladakh. At that time, the Indian authorities claimed that over 30 Chinese soldiers were also killed in the Galwan clash, although Beijing has never released official figures. The worst incident between the two countries took place amidst a de-escalation process in the Galwan area that had started in the second week of June 2025, after a month-long standoff between troops at several points along the LAC in Ladakh and Sikkim. The Indian and Chinese Armies got involved in such a bloody clash after 45 years and the incident soured bilateral relations. Now, the two Asian neighbours have started normalising their ties.

Meanwhile,

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Published by Koushik Das

Koushik Das (born on May 16, 1976 in Kolkata) is a career journalist. Based in the Indian capital of New Delhi, Koushik writes mainly about foreign policies and current geopolitical issues, and rarely about other topics. His own political ideas are highly influenced by Antonio Gramsci, Louis Althusser, Michel Foucault, Michael Oakeshott and others. English philosopher and political theorist Oakeshott (Dec 11, 1901-Dec 19, 1990) says that “in political activity, men sail a boundless and bottomless sea. There is neither harbour for shelter nor floor for anchorage, neither starting-place, nor appointed destination. But we have to keep afloat”. (Rationalism in Politics, 1962) As a student of Political Science, Koushik loves to share his views on issues, which have great impacts on his thought process (and also on India, South Asia and of course on the global community), with his readers through his website – Boundless Ocean of Politics. By doing so, he tries to keep himself afloat. You will find some of his articles in https://inserbia.info/today/ (https://inserbia.info/today/author/kou_das13_i/), as he has been trying to assess the global geopolitics since 2003. You can also mail him at kousdas@gmail.com View all posts by Koushik Das