The following is the Congressional Research Service May 17, 2021 In Focus report, Chinese Nuclear and Missile Proliferation
From the report
The U.S. government has continued to express concerns about China’s record concerning the proliferation of nuclear- and missile-related technologies to other countries, with more recent focus on the threat of Chinese acquisition of U.S.-origin nuclear technology. Official U.S. government reports indicate that the Chinese government has apparently ended its direct involvement in the transfer of nuclear- and missile-related items, but Chinese-based companies and individuals continue to export goods relevant to those items, particularly to Iran and North Korea. U.S. officials have also raised concerns about entities operating in China that provide other forms of support for proliferation-sensitive activities, such as illicit finance and money laundering.
China did not oppose new states’ acquisition of nuclear weapons during the 1960s and 1970s, the Department of State wrote in a declassified January 1998 report to Congress. According to a 1983 National Intelligence Estimate (NIE), China had exported “nuclear materials since 1981” that were not subject to International Atomic Energy Agency (IAEA) safeguards. Beijing did so “mainly to earn hard currency,” the estimate assesses, explaining that the
Chinese became aware in 1979 that they had insufficient resources for their initially grandiose modernization program and that they needed to generate more revenue through expanded foreign trade. Accordingly, the State Council directed its subordinate ministries in late 1979 to begin selling surpluses.
Consequently, according to the NIE, Beijing ended its “abstention from commercial trade in conventional arms and nuclear materials.” During the 1980s and 1990s, China transferred nuclear and missile technology to other countries’ weapons programs. China provided assistance to Pakistan’s nuclear weapons program and engaged in nuclear cooperation with Iran. Beijing exported missiles to Pakistan, Saudi Arabia, and Iran.
According to U.S. government reports and official statements, China also significantly curtailed its nuclear- and missile-related transfers during the 1990s; Beijing also committed to improving its export controls. For example, the 1998 State Department report cited above noted China’s 1996 pledge to refrain from assisting unsafeguarded nuclear facilities and 1997 changes to Chinese nuclear export policy, as well as other Chinese nonproliferation efforts.
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