China Conducted Secret Nuclear Test Just 7 Days After Galwan Clash, US Reveals

Beijing/Washington: The United States has accused China of carrying out a covert nuclear test on June 22, 2020—just a week after its military clash with India in the Galwan Valley on June 15. According to US officials, China conducted at least one “yield-producing nuclear test” in violation of existing test-ban commitments, though it was designed to avoid a full nuclear detonation.

What Was the Test?

The test reportedly involved the use of nuclear materials, but in a controlled manner that did not produce a mushroom cloud or a large-scale explosion. Such “sub-critical” or “zero-yield” tests are intended to validate weapon designs, check performance, and develop new, compact nuclear warheads with far greater efficiency than older models. The explosive yield of such tests is measured in kilotons (Kt) or megatons (Mt), indicating the energy released.

US Accusations and Monitoring

Thomas Dinanno, US Under Secretary for Arms Control and International Security, told the Geneva-based Disarmament Conference that China deliberately tried to conceal the test, including using methods to reduce seismic detectability. The test was conducted at the Lop Nur site, where large-scale excavation and containment measures were employed.

The US relies on a global network of hundreds of seismic monitoring stations under the Comprehensive Nuclear-Test-Ban Treaty (CTBT) to detect nuclear tests. While North Korea remains the only country to have openly tested nuclear weapons after 2000, these allegations, if confirmed, would make China the second.

China’s Response

China’s Deputy Permanent Representative to the UN and other international organizations in Geneva, Ambassador Shen Jian, strongly denied the allegations, calling them “exaggerated and false.” He accused the United States of attempting to escalate the arms race.

Concerns Over China’s Nuclear Arsenal

US officials have raised long-standing concerns over the expansion of China’s nuclear capabilities, including warheads and delivery systems. During a military parade in Beijing in September 2025, China displayed multiple missiles capable of delivering nuclear weapons to the US. Pentagon reports indicate work on new intercontinental ballistic missile silos and nuclear-capable hypersonic glide vehicles. Current estimates suggest China may have around 600 nuclear warheads, potentially rising to 1,000 by 2030 and 1,500 by 2035.

The timing of the test, shortly after the Galwan clash, and its secrecy, underscores Beijing’s continuing focus on advancing its strategic nuclear capabilities while avoiding international detection.