China conducts a nuclear test for DF-31 warhead at Area C (Beishan), Lop Nur, its prominence being due to the Cox Report.

The Report of the Select Committee on U.S. National Security and Military/Commercial Concerns with the People's Republic of China, commonly known as the Cox Report after Representative Christopher Cox, is a classified U.S. government document reporting on the People's Republic of China's covert operations within the United States during the 1980s and 1990s. The redacted version of the report was released to the public on May 25, 1999.

The Dong Feng 31 (simplified Chinese: 东风-31; traditional Chinese: 東風-31; lit. 'East Wind-31'; NATO reporting name CSS-10) is a third-generation long-range, road-mobile, three stage, solid-fuel rocket intercontinental ballistic missile (ICBM) in the Dongfeng missile series developed by the People's Republic of China. It is designed to carry a single 1-megaton thermonuclear weapon. It is a land-based variant of the submarine-launched JL-2. It is operated by the Second Artillery Corps (SAC) which, in 2009, was estimated to have under 15 DF-31 missiles and under 15 DF-31A missiles in inventory. US Air Force National Air and Space Intelligence Center estimates that as of June 2017, five to ten Mod 1 and over fifteen Mod 2 launchers were operationally deployed.