On February 17, 2026, Assistant Secretary of State Christopher Yeaw presented new details regarding an alleged Chinese underground nuclear test conducted on June 22, 2020, at the Lop Nor test grounds in western China. Yeaw stated that a remote seismic station in Kazakhstan registered a magnitude 2.75 "explosion" 720km away, asserting the data was inconsistent with mining blasts or earthquakes and indicative of a nuclear explosive test, potentially concealed through decoupling. While the Comprehensive Test Ban Treaty Organisation (CTBTO) noted two small seismic events spaced 12 seconds apart, it stated insufficient data existed to confirm the allegation with confidence, as the events were far below their detection threshold for nuclear test explosions. This comes as the US, under President Donald Trump, urges China to join negotiations for a replacement to the expired New START treaty, a proposal China has rejected due to its smaller nuclear arsenal compared to the US and Russia.