The United States has accused China of carrying out a covert nuclear explosive test on June 22, 2020, days after the deadly Galwan Valley clash between Indian and Chinese troops that left 20 Indian soldiers dead. The allegation surfaced during discussions on nuclear arms control following the expiry of the New START Treaty.
The pact, signed in 2010 by US President Barack Obama and Russian President Dmitry Medvedev, capped the deployment of missiles and nuclear warheads for both countries. However, shifting global dynamics and the treaty&rsquo;s limitations have intensified concerns over strategic stability.
At a disarmament conference in Geneva, a senior US official claimed Washington was aware of Chinese nuclear tests, including preparations for explosions with significant yields. The official also alleged that the Chinese military attempted to obscure such activities by using techniques designed to weaken seismic detection.
The timing of one alleged test, a week after the June 15, 2020, Galwan confrontation, added to geopolitical sensitivities. While India confirmed the deaths of its soldiers, China publicly acknowledged fewer casualties despite reports suggesting higher losses.
US officials argued that the existing treaty framework no longer reflects current realities, particularly as some nuclear powers expand their arsenals while others remain outside the agreement. They stressed the need for a new arms-control architecture capable of addressing modern threats and ensuring verifiable commitments.
Washington has also indicated it will strengthen its nuclear deterrence in response to what it views as destabilising behaviour by rival powers. Calls have grown within the US to bring China into any future arms-control arrangement alongside Russia.
Beijing, however, rejected claims of a &ldquo;China nuclear threat,&rdquo; accusing the US of fuelling an arms race. Chinese representatives maintained that their nuclear stockpile is far smaller than that of the US and Russia and reiterated that the country is not prepared to join trilateral disarmament negotiations at this stage.
Diplomats have voiced concern over the renewed accusations, warning that escalating mistrust could further strain global non-proliferation efforts.
Both China and the United States have signed the Comprehensive Nuclear-Test-Ban Treaty, which prohibits explosive testing, though neither nation has ratified it. Russia had ratified the treaty but withdrew its ratification in 2023.
New START was originally set to expire in 2021 but received a five-year extension. Russia later suspended participation in 2023 amid tensions with the West over the Ukraine war, though it signalled willingness to continue observing certain limits temporarily to allow room for future negotiations.
As the last major pillar of US-Russia nuclear arms control weakens, discussions are increasingly focused on crafting a broader agreement that reflects today&rsquo;s multipolar nuclear landscape.

Alleged 2020 blast surfaces amid New START expiry and rising arms tensions

US Accuses China of Secret Nuke Test After Galwan

Alleged 2020 blast surfaces amid New START expiry and rising arms tensions

February 8, 2026 | 15:33 IST