The United States accused China of conducting a covert nuclear explosive test on June 22, 2020, just a week after the deadly Galwan Valley clash in Ladakh, where 20 Indian soldiers died.
US Under Secretary of State for Arms Control Thomas G. DiNanno said Beijing used “decoupling” techniques to evade seismic monitoring and conceal yield-producing nuclear tests. He emphasised that no Chinese nuclear weapons were covered under the New START treaty, pointing to unchecked expansion.
The allegation coincided with the expiry of the New START treaty, the last binding nuclear arms pact between Washington and Moscow. US officials, including Secretary of State Marco Rubio, warned that Russia and China are expanding nuclear forces without limits. Washington called for a new global nuclear architecture that includes China.
China rejected participation in disarmament talks, citing its smaller arsenal of about 600 warheads compared to the US and Russia. Chinese foreign ministry spokesperson Lin Jian said Beijing will not join negotiations at this stage but urged Washington to resume talks with Moscow.
The timing of the alleged nuclear test, days after the Galwan clash, underscored China’s aggressive posture along the Line of Actual Control. Intelligence reports estimated Chinese casualties at more than 30, though Beijing officially acknowledged only four deaths.
The New START treaty, signed in 2010, limited each side to 1,550 deployed warheads. Russia suspended participation in 2023, and the treaty formally expired, ending five decades of nuclear limits. US President Donald Trump insisted that any future treaty must include China, but Beijing continues to resist.
