A major topic of diplomatic discussion  between United States and China has been U.S. allegations that China breached the Comprehensive Nuclear-Test-Ban Treaty of 1996, or CTBT.  The treaty isn’t legally in force because not enough nations have ratified it. As a result, the treaty’s provisions for conducting short-notice inspections aren’t in effect. But China, Russia and the U.S. say they are abiding by its terms. That treaty allows signatories to take steps to ensure the safety and reliability of nuclear weapons, including experiments involving fissile material, as long as they don’t result in a nuclear-explosive yield.

But the Trump administration has alleged that China has gone further by secretly carrying out very low-yield nuclear tests, including one at its Lop Nur site in northwest China in June 2020. Chinese officials have vociferously denied the accusation, putting the two sides squarely at odds. In October 2025, Trump said he would order the resumption of U.S. nuclear testing on an “equal basis” with China and Russia if those nations didn’t stop their suspected low-level tests….

The U.S. also is pushing China to provide transparency on its nuclear-force levels. China currently has over 600 nuclear weapons but is on track to have more than 1,000 by 2030, according to an annual Pentagon report on China’s military capabilities sent to Congress in 2025. “It’s hard to overstate the neuralgia that China has to any kind of meaningful discussion about arms control with the United States,” said Jonathan Czin of the Brookings Institution, a former senior U.S. intelligence official on China. “They really see it as a trap, and as a way for the United States, in their eyes, to contain and suppress China.”

Excerpt from Michael R. Gordon et al., Trump Administration Presses China on Suspected Nuclear Tests in Confidential Talks, WSJ, Sept. 24, 2026