Iran's first nuclear power plant was opened Saturday by Iranian and Russian nuclear officials in the southern port city of Bushehr after a delay of almost three decades.

With the opening of the Russian-built plant, the 82 tonnes of nuclear fuel that were already delivered to Iran by Russia were unsealed by the International Atomic Energy Agency (IAEA) and kept in an outdoor "fuel pool" near the reactor.

The fuel is to be gradually injected from this pool into the reactor under IAEA supervision, and the plant was expected to go online in November at the earliest and be connected to the national grid.

The plant was scheduled to reach its maximum capacity of 1,000 megawatts within six or seven months.

Iranian atomic chief Ali-Akbar Salehi and the head of Russia's nuclear energy company, Sergei Kiriyenko, attended the inaugural ceremony.