<<< Click for the begnning of the history of the nuclear weapon age following 1970.

May 26, 1972 Nixon and Soviet Premier Leonid Brezhnev sign Strategic Arms Limitation Talks (SALT I), which limits antiballistic missile launchers in each country and imposes a 5-year freeze on testing and deployment if ICBMs and SLBMs at 1972 levels.

May 18, 1974 India becomes the sixth country to successfully test a nuclear weapon, exploding a plutonium implosion bomb at Pokharan in the Rajasthan Desert.

July 7, 1977 The United States successfully tests a neutron bomb. The primary lethal effects of a neutron bomb, also known as an enhanced-radiation weapon, come from the radiation damage caused by the neutrons it emits.

June 18, 1979 The United States and the Soviet Union sign SALT II, which restricts the number of strategic offensive weapons. The United States does not ratify the treaty after the Soviet Union invades Afghanistan in December.

March 23, 1983 President Ronald Reagan announces the United States will embark on an extensive research and development program to examine the feasibility of a missile defense program. The Strategic Defense Initiative is later dubbed "Star Wars."

December 1987 The United States and the Soviet Union sign the Intermediate-Range Nuclear Forces Treaty, which requires the elimination of all intermediate-range missiles (IRMs), shorter-range missiles (SRMs) and associated equipment.

July 1991 Soviet Premier Mikhail Gorbachev and U.S. President George Bush sign Strategic Arms Reduction Treaty (START I). The bilateral agreement sets a ceiling of 1,600 strategic nuclear delivery vehicles and 6,000 "accountable" warheads for each country. It is the first treaty that requires the two superpowers to begin dismantling parts of their respective nuclear arsenals.

Dec. 5, 1991 Bush signs the Missile Defense Act of 1991, which mandates the Department of Defense develop a missile defense system.

January 1993 Russian President Boris Yeltsin and Bush sign START II, which requires the two countries to destroy 30 percent of long range nuclear missiles and eliminate land-based multiple-warhead missiles - or about one-half of their strategic nuclear weapons.

March 1993 South Africa announces it built six nuclear weapons, but had them dismantled and destroyed. South Africa becomes the only country known to have developed nuclear weapons, and then voluntarily relinquished that capability.

Sept. 2, 1995 France comes under fire from the international community for conducting a new nuclear detonation test in Mururoa atoll, the Pacific Ocean. France says the blasts are designed to test software so it can conduct future tests in computers, without actual detonations. In all, France conducted 210 nuclear tests, about 17 of them in the 1960s in the Sahara Desert and the remainder in French Polynesia.

July 29, 1996 China conducts its last nuclear weapons test, exploding a bomb near Lop Nor. China has exploded 45 nuclear bombs since 1969.

Sept. 10, 1996 The United States, Russia, the United Kingdom and 90 other nations sign the Comprehensive Test Ban Treaty, which would ban any and all nuclear tests above and below the Earth's surface. India and Pakistan refuse to sign.

May 11, 1998 As part of its standoff with Pakistan and to show military might, India conducts its second round of nuclear weapons tests - its first was in 1974. It explodes two atomic bombs and one hydrogen bomb. It completes a total of five tests in three days.

May 30, 1998 Pakistan conducts five nuclear weapons tests in three in response to the India tests. The Asian sub-continent is pitched into an unstable arms race.

July 23, 1999 President Bill Clinton signs the National Missile Defense act and says threat, cost, technological status of national missile defense and adherence to a renegotiated ABM treaty are the four criteria in making his decision to deploy such a system.

April 10, 2001 Russia, China and North Korea tell the UN Disarmament Commission that an U.S. missile defense system would threaten international security, trigger a new arms race and undermine the ABM treaty.

Dec. 13, 2001 President Bush pulls out of the 1972 Anti-Ballistic Missile treaty, denouncing it as a relic of the Cold War and a roadblock to mounting a U.S. defense against missile attack. Russian President Vladimir Putin calls the U.S. decision a "mistake."

Oct. 16, 2002 North Korea admits to Washington that it has a secret nuclear weapons program, news that changes the political landscape in East Asia and sets back hopes that North Korea was on the road to becoming a more benign presence in the region. White House officials say they don't know if the North Koreans have weapons, or just the material to make them. But the U.S. does know that the North Koreans have not done any testing.

Jan. 10, 2003 Amid escalating tensions with the U.S. over the resumption of its nuclear weapons program, North Korea withdraws from the Nuclear Nonproliferation Treaty. The communist state claims that leaving the treaty frees it from safeguard obligations to the U.N. International Atomic Energy Agency.

Feb. 9, 2003 Iran acknowledges for the first time that it has uranium ore reserves and that it will reprocess the spent fuel. But it insists the nuclear program was designed solely for civilian use.

Aug. 26, 2003 U.N. inspectors report finding traces of highly enriched, weapons-grade uranium at an Iranian nuclear facility.

Sept. 9, 2003 Edward Teller, "father of the H-bomb" dies.

April 2, 2004 International Atomic Energy Agency (IAEA) reports finding traces of bomb-grade uranium in Iran at sites other than two already named.

Jan. 22, 2005 North Korea announces it is a nuclear weapons state.

Oct. 7, 2005 The International Atomic Energy Agency (IAEA) and its head, Mohamed ElBaradei, win the Nobel Peace Prize.

Aug. 31, 2006 A report by the International Atomic Energy Agency said that Iran shows no signs of freezing uranium enrichment, opening the way for U.N. Security Council sanctions against Tehran as a Security Council deadline for it to cease the activity passed.

Oct. 9, 2006 North Korea announced that it had set off an atomic weapon underground, a test that thrusts the secretive communist state into the elite club of nuclear-armed nations. The United States, Japan, China and Britain led a chorus of criticism and urged action by the United Nations Security Council in response to the reported test.

Feb. 13, 2007 Negotiators reach agreement at six-nation talks on initial steps for North Korea's disarmament. U.S. hails deal as "a very important first step" toward ridding the Pyongyang government of all atomic weapons and capabilities.

Feb. 22, 2007 U.N. nuclear chief Mohamed ElBaradei said that Iran has refused to suspend uranium enrichment as demanded by the U.N. Security Council. In a report to the International Atomic Energy Agency's board of government, ElBaradei said "Iran has not suspended its enrichment related activities" and was continuing a variety of enrichment activities.

Sept. 6, 2007 An Israeli Air Force strike against Syria targeted a partly constructed nuclear reactor, apparently of North Korean design, based on independent examination of digital imagery of the bombed site.

April 24, 2008 The White House said North Korea assisted Syria's secret nuclear program and that the reactor bombed by Israel in September 2007 was not intended for peaceful purposes. After seven months of silence, the administration said that after the reactor was damaged beyond repair, Syria tried to bury evidence of its existence. The U.S. says Syria "must come clean before the world" about its nuclear activities. The White House called North Korea's nuclear assistance to Syria a "dangerous manifestation" of that country's nuclear weapons program and its proliferation activities.