Nuclear Security & Deterrence Monitor Vol. 30 No. 8
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Nuclear Security & Deterrence Monitor
Article 3 of 11
February 27, 2026

US intelligence: China conducted 2020 explosive nuclear test, revamping arsenal

By ExchangeMonitor

After the State Department publicly revealed China secretly conducted an explosive nuclear test in 2020, despite a self-imposed ban from 1996, intelligence agencies are saying China’s purpose is to completely transform the country’s nuclear arsenal, according to CNN.

The Feb. 21 article said sources familiar with U.S. intelligence assessments said the nuclear test could mean Beijing has shifted its nuclear strategy and investing in its nuclear arsenal to push it to “peer status” with Russia and the United States, despite its smaller, though rapidly expanding, nuclear arsenal. Eventually, China could have technical capabilities possessed by neither the U.S. nor Russia, CNN said.

On Feb. 6, one day after the expiration of the New Strategic Arms Reduction Treaty between the U.S. and Russia, Thomas Dinanno, the undersecretary of state for arms control and international security, gave a statement revealing “the U.S. Government is aware that China has conducted nuclear explosive tests, including preparing for tests with designated yields in the hundreds of tons.” He said many asked what President Donald Trump meant when, in October, Trump posted on social media saying the U.S. would start testing nuclear weapons “on an equal basis” with Russia and China.

“The PLA [People’s Liberation Army, or the armed forces of the Communist Party of China] sought to conceal testing by obfuscating the nuclear explosions because it recognized these tests violate test ban commitments,” Dinanno said, referring to China’s 1996 self-imposed moratorium of nuclear tests. “China has used decoupling – a method to decrease the effectiveness of seismic monitoring – to hide their activities from the world” and “conducted one such yield producing nuclear test on June 22 of 2020.”

Dinanno also said an annual U.S. compliance report assessed Russia also “failed to maintain its testing moratorium by conducting supercritical nuclear weapons tests,” but did not elaborate.

This confluence of factors – serial Russian violations, growth of worldwide stockpiles, and flaws in New START’s design and implementation – gives the United States a clear imperative to call for a new architecture that addresses the threats of today, not those of a bygone era,” Dinanno said.