1967

United States delivers first research reactor to Iran.

1974

KWU, a subsidiary of Germany's Siemens begins construction of a nuclear power plant in Bushehr.

1979

Workers halt construction in Bushehr after Khomeini seizes power. KWU end its operations in Iran.

1987

The Bushehr facility is heavily damaged in bombing raids conducted in the Iran-Iraq war.

1995

Russia resumes construction of two light-water reactors in Bushehr and says it will store Iran's spent nuclear fuel. The US protests, fearing the nuclear technology and fuel will be put to military use.

2001

US intelligence services first suspect that Iran has military nuclear facilities.

2002

Exiled members of the Iranian opposition claim that Tehran has uranium enrichment facilities in Natanz and a heavy-water reactor in Arak. The US accuses Iran of operating a secret military nuclear program.

2003

President Khatami states that Iran wants to develop a full nuclear cycle; inspectors from the International Atomic Energy Agency (IAEA) visit a facility for the production of enriched uranium at Natanz. The IAEA says that Iran's portrayal of its facilities is patchy, but it does not allege that Tehran has a weapons program. Iran reaches a deal with the European Union to cease any uranium enrichment.