DidChinapull off one of the most sophisticated concealed nuclear tests in history? Or is theUSbuilding a case to restart its own testing programme?
Washington says Beijing secretly detonated a nuclear device at its Lop Nur test site on 22 June 2020. The method allegedly used: 'decoupling' — setting off an explosion inside a massive underground cavity to dampen seismic signals. The problem? The global nuclear watchdog says it detected nothing consistent with a nuclear test that day.
The accusation came from Under Secretary of State Thomas DiNanno at a UN disarmament conference in Geneva on 6 February 2026.
'I can reveal that the US government is aware that China has conducted nuclear explosive tests, including preparing for tests with designated yields in the hundreds of tons,' DiNanno said, NPR reported. 'China has used decoupling — a method to decrease the effectiveness of seismic monitoring — to hide its activities from the world.'
Days later, Assistant Secretary of State Christopher Yeaw provided more details at the Hudson Institute. A monitoring station in Kazakhstan picked up a magnitude 2.75 seismic event roughly 450 miles from Lop Nur on that June 2020 date.
'There is very little possibility that it is anything other than an explosion, a singular explosion,' Yeaw said, according to Newsweek.
The Comprehensive Nuclear-Test-Ban Treaty Organisation (CTBTO) confirmed its monitoring station recorded 'two very small seismic events, 12 seconds apart' on 22 June 2020. But Executive Secretary Robert Floyd was blunt: 'With this data alone, it is not possible to assess the cause of these events with confidence.'
The CTBTO's system can detect nuclear explosions with yields of approximately 500 tonnes of TNT or greater. These events fell far below that threshold.
A Centre for Strategic and International Studies satellite analysis of the Lop Nur site 'did not provide any conclusive findings to support or disprove the recent US allegations.' The researchers noted that Lop Nur is vast — it's possible that testing occurred elsewhere on the site with no visible optical indicators.
'The US accusation of Chinese nuclear explosive tests is completely groundless,' Foreign Ministry spokesperson Lin Jian said during a press conference. 'China opposes the US fabrication of pretexts for its own resumption of nuclear tests.'
Source: International Business Times UK
