U.S. Expands Claim of a 2020 Secret Chinese Nuclear Test at Lop Nor

The allegation surfaces as New START lapses, with Washington signaling readiness to resume testing to avoid perceived disadvantage.

Overview

At a Hudson Institute event, arms-control official Christopher Yeaw cited new analysis of a magnitude‑2.75 signal on 22 June 2020 near Lop Nor that he says indicates a single underground explosion.
Yeaw argued the data are inconsistent with earthquakes or mining blasts and suggested China used seismic decoupling to suppress the signal.
CTBTO chief Robert Floyd said its PS23 station in Kazakhstan recorded two very small events 12 seconds apart that fall below its reliable detection threshold, so the cause cannot be determined.
Beijing rejected the accusation as baseless and politically motivated, with its Washington embassy urging the U.S. to uphold the global testing moratorium.
The dispute follows the expiration of New START this month, as Washington pushes for a trilateral framework, cites Pentagon estimates of China’s 600+ warheads rising toward 1,000 by 2030, and signals it is prepared to resume U.S. nuclear tests on an “equal basis.”