A senior US official has provided new details on an alleged underground nuclear test by China at its Lop Nor site in June 2020. This comes amid heightened tensions over nuclear arms control following the expiration of the New START treaty.
Key Allegations from US Officials
Christopher Yeaw, Assistant Secretary of State, spoke at the Hudson Institute in Washington on February 17, 2026, claiming a seismic event of magnitude 2.75-2.76 was detected by a station in Kazakhstan, about 450 miles from Lop Nor. He described it as a “yield-producing” test involving a runaway chain reaction, with China using “decoupling” techniques—detonating deep underground—to mask the blast’s magnitude. Yeaw noted preparations for tests with yields in the hundreds of tons but did not specify the exact size.
China’s Response and Independent Verification
China’s Foreign Ministry has dismissed the claims as “outright lies” and “entirely unfounded,” accusing the US of fabricating excuses to resume its own testing. The Chinese embassy in Washington called the allegations “entirely unfounded.” The Comprehensive Test Ban Treaty Organization (CTBTO) stated that available data is insufficient to confirm the claims.
Broader Context
The accusations follow initial US disclosures earlier in February 2026 by Undersecretary Thomas DiNanno at a Geneva conference. President Donald Trump is pushing for trilateral talks with China and Russia to replace New START, which expired on February 5, 2026, amid fears of a new arms race. China, which last officially tested in 1996, has signed but not ratified the 1996 Comprehensive Nuclear-Test-Ban Treaty.
