US official says China secretly tested a nuclear device days after Galwan clash

US official says China secretly tested a nuclear device days after Galwan clash

• US claims China conducted secret nuclear test post-Galwan clash in June 2020.
• China denies the claim; no independent confirmation of nuclear explosion exists
• The allegation raises concerns about nuclear transparency amid US-China tensions

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A senior US official has claimed that China carried out a secret nuclear explosive test just days after the deadly Galwan Valley clash between Indian and Chinese troops in June 2020. The allegation, made by former US Under Secretary of State Thomas G DiNanno, has once again put the spotlight on how closely major powers are really sticking to global testing norms.

According to DiNanno, the test took place on June 22, 2020, about a week after the June 15 Galwan confrontation in eastern Ladakh. That clash was the most serious border violence between India and China in decades and led to casualties on both sides, sharply escalating tensions along the Line of Actual Control.

DiNanno alleged that China conducted low yield nuclear explosive tests, possibly in the range of a few hundred tons of TNT equivalent. He also claimed that China used a technique known as “decoupling” to make the blast harder to detect. In simple terms, decoupling involves setting off an underground explosion inside a large cavity, which can muffle the seismic signals that monitoring stations look for. Arms control experts have debated this method for years, but proving its use in any specific case is extremely difficult.

China has consistently denied conducting nuclear tests in violation of its commitments. Beijing has signed the Comprehensive Nuclear Test Ban Treaty but, like the United States, has not ratified it. Both countries observe a voluntary moratorium on nuclear testing, though the treaty itself has not formally come into force.

There has been no public, independent confirmation that a nuclear explosion occurred on the date mentioned. The global monitoring network set up under the Comprehensive Nuclear Test Ban Treaty Organisation tracks seismic activity and other indicators linked to nuclear blasts. So far, publicly available data has not clearly established that such a test took place.

Still, the allegation matters. It comes at a time when US China rivalry is already intense, and when India’s border tensions with China remain unresolved. Even an unproven claim of secret testing feeds into wider concerns about trust, verification and military competition among nuclear armed powers.

For now, it remains a claim by a US official that China strongly rejects. But it shows how sensitive the issue of nuclear transparency continues to be, especially when geopolitics is already on edge.