China conducted secret nuclear test, US claims a day after arms proposal

The United States has accused China of conducting secret low-yield nuclear explosive tests in 2020, allegedly attempting to conceal them by detonating devices in large underground cavities to muffle seismic signals—a technique known as “decoupling.” This method can make nuclear tests difficult to detect through global seismic monitoring, which is crucial for verifying compliance with nuclear test bans. The alleged test reportedly occurred just one day after the expiration of the New START treaty, coinciding with a new arms control proposal by the US. China has neither confirmed nor denied these allegations, and no definitive proof has been publicly presented. These accusations come amid broader tensions over nuclear arms control, with Russia offering a temporary extension to the New START treaty, which the US declined, citing concerns about the treaty’s terms and compliance. The US claims China’s nuclear arsenal, officially estimated at around 600 warheads, is growing and that Beijing has little incentive to join non-proliferation agreements while lagging behind the US and Russia, each