China has a mixed nuclear proliferation record:

_1985: The U.S.-China Nuclear Cooperation Agreement is signed and China agrees to provide nuclear assistance only for peaceful purposes. In 1986, Congress requires the president to certify China isn't violating the new pact before U.S. companies can help build Chinese nuclear reactors for peaceful use. No president has made such a declaration.

_1992: China accedes to the Non-proliferation Treaty. But it is suspected of continuing to help nations such as Pakistan that don't let the International Atomic Energy Agency inspect to ensure peaceful nuclear uses.

_1993: China signs the Chemical Weapons Convention, which its National People's Congress approves in December 1996.

_1994: China says it will abide by the Missile Technology Control Regime and not export ground-to-ground missiles. But it remains accused of exporting nuclear technology and components to Iran, Syria and Algeria as well as missiles that can carry nuclear warheads, chemical and biological weapons.

_1994: The Chinese help the United States gain an agreement with North Korea to freeze its nuclear weapons program in exchange for help in building reactors to provide energy.

_1996: China stops testing nuclear weapons and signs the Comprehensive Test Ban Treaty.

_May 1996: China says it will no longer assist unsafeguarded nuclear facilities. The Clinton administration has since stated it has no reason to believe China has violated this commitment. The agreement came after the CIA found China had sold 5,000 ring magnets to Pakistan for its main plant to enrich uranium, which can be used for bombs.

_September 1997: China issues export rules to prevent the spread of nuclear technologies to nations for nonpeaceful purposes. The Clinton administration has the untested regulations under review.

_October 1997: China plans to join the Zanger Group, which prohibits providing nuclear technologies to nonpeaceful facilities. But China refuses to join the Nuclear Suppliers Group, which has more stringent rules to stop nuclear technology from being diverted to military uses by nations.