(Reuters) - Here is a chronology of events since it first emerged Iran was carrying out sensitive work that it could use to make atomic bombs. Iran says its programme is for peaceful energy generation.
August 2002 - The exiled opposition National Council of Resistance of Iran reports the existence of a uranium enrichment facility at Natanz and a heavy water plant at Arak.
June 2003 - An IAEA report says Iran has failed to comply with nuclear Non-Proliferation Treaty.
November 2004 - Iran promises EU negotiators it will suspend all nuclear fuel processing and reprocessing work.
September 2, 2005 - IAEA report confirms Iran has resumed uranium conversion at Isfahan.
February 4, 2006 - IAEA votes to report Iran to the U.N. Security Council. Iran ends snap U.N. nuclear inspections the next day.
April 11 - Ahmadinejad declares that Iran has produced its first batch of enriched uranium. World powers condemn Iran for advancing its programme in defiance of the United Nations.
June 5 - EU foreign policy chief Javier Solana delivers a package of incentives from world powers if Iran agrees to halt uranium enrichment.
December 23 - Security Council votes for sanctions and gives 60 days to suspend enrichment. Iran calls the resolution illegal.
March 24, 2007 - The Security Council unanimously approves further arms and financial sanctions against Iran.
April 18 - IAEA says Iran has started up more than 1,300 centrifuge machines in an accelerating campaign to lay a basis for “industrial scale” enrichment in the Natanz complex.
August 21 - Iran and the IAEA say they agreed a timeline for answering outstanding questions about Iran’s nuclear programme.
October 24 - The United States imposes new sanctions on Iran and accuses its Revolutionary Guard of spreading weapons of mass destruction.
November 2 - Six powers - Britain, France, Germany, the United States, Russia and China - agree to push ahead with a third round of tougher sanctions.
December 3 - A U.S. National Intelligence Estimate says Iran put its bid to build a nuclear bomb on hold in 2003 and it remains on hold.
December 5 - Ahmadinejad declares victory over the U.S. and IAEA head Mohamed ElBaradei says Iran has been “somewhat vindicated”.
December 11 - The opposition NCRI says Iran did shut down its programme in 2003 but restarted it a year later. The group says recent U.S. analysis gives the wrong impression.
January 11-12, 2008 - ElBaradei makes a rare visit to Tehran to push for swifter cooperation in wrapping up the IAEA inquiry.
March 3 - U.N. Security Council adopts third sanctions resolution targeted at Iran’s nuclear programme.
May 14 - Russia’s foreign minister says that the ‘Six’ could put concrete offers on the negotiating table and could guarantee Tehran’s security. The White House later says security guarantees for Iran were not being considered.
May 26 - The IAEA says Iran’s alleged research into nuclear warheads is a matter of serious concern and Tehran should provide more information on its missile-related activities.
June 1 - Iran says it might have to limit its cooperation with the IAEA, after the agency’s report.
June 14 - Solana, visiting Tehran, hands Iran an offer by the six powers of trade and other benefits, but Iran’s government again rules out any suspension of nuclear activities.
U.S. President George W. Bush says he is disappointed Iran has rejected the proposition, which he says was generous.
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Writing by David Cutler, London Editorial Reference Unit;