Arms Control and Nonproliferation

The State Department has released new intelligence indicating that a tiny June 22, 2020 seismic event near China’s Lop Nur site was 'quite consistent' with a low‑yield nuclear explosion, with Assistant Secretary for Arms Control and Nonproliferation Christopher Yeaw saying there is 'very little possibility' it was anything other than a single explosion. Speaking at the Hudson Institute on Feb. 17, 2026, Yeaw said a remote station in Kazakhstan recorded a 2.75‑magnitude tremor roughly 450 miles from Lop Nur and argued the waveform ratios matched what would be expected from a clandestine nuclear test, raising fresh questions about Beijing’s adherence to the Comprehensive Nuclear‑Test‑Ban Treaty it has signed but not ratified. Independent seismologists at NORSAR, which monitors for nuclear tests, agree the signal could be an explosion but stress it was weak and detected at only one station, saying current data are not strong or conclusive enough to confirm or rule out a nuclear test. China’s Foreign Ministry has called the U.S. allegation 'completely groundless' and accuses Washington of fabricating a pretext to resume its own nuclear testing. The disclosure comes amid China’s rapid nuclear‑arsenal expansion and visible construction at Lop Nur, intensifying arms‑control tensions as U.S. and Chinese nuclear limits remain largely unconstrained.