The United States accused Beijing on Friday of conducting a secret nuclear test in 2020 as it called for a new, broader arms control treaty that would bring in China as well as Russia.

The accusations at a global disarmament conference highlighted serious tension between Washington and Beijing at a pivotal moment in nuclear arms control, a day after the treaty limiting U.S. and Russian missile and warhead deployments expired.

¡°I can reveal that 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,¡± U.S. Under Secretary of State for Arms ?Control and International Security Thomas DiNanno told a Disarmament Conference in Geneva.