UPDATED Russia has agreed to build up to eight new nuclear power reactor units in Iran - four at Bushehr and four at another, yet to be determined site.

UPDATED Iran has rejected the charge it has violated one of the commitments it made in the Joint Plan of Action it agreed at a meeting with P5+1 leaders in Geneva last year.

An International Atomic Energy Agency report has confirmed that Iran has completed steps to convert its inventory of 20% enriched uranium hexafluoride into forms that are less of a proliferation risk as political leaders agree to a six-month extension of an action plan aimed at curbing Iranian enrichment activities.

Russian regulator Rostechnadzor has agreed to continue and expand its provision of consulting services to its Iranian counterpart for the operation of the Bushehr nuclear power plant.

Russia and Iran have reportedly reached a preliminary agreement for the construction of two more units at the Bushehr nuclear power plant. The first unit at Bushehr, completed by Russia, is already in full operation.

Iran will begin suspending parts of its uranium enrichment program and downblending its stockpile of uranium enriched up to 20% over the next six months in return for modest relief from international sanctions.

Iran is to limit its uranium enrichment activities in return for some easing of economic sanctions. The new agreement with the P5+1 countries is seen as a significant step towards a long-term comprehensive solution.

Iran has said it will cooperate on resolving "all outstanding issues" that the International Atomic Energy Agency has concerning its nuclear program. Access is to be granted to heavy water facilities and the Gachin uranium mine.

The handover of the Bushehr nuclear power plant by Russian constructors to its Iranian customer has formally begun with a ceremony attended by the heads of NIAEP-ASE and the Atomic Energy Organisation of Iran.

Former foreign minister Ali Akbar Salehi has returned to the Atomic Energy Organisation of Iran as its head. He will soon lead negotiations with Russia on the potential supply of new nuclear reactors, set to begin once Bushehr is handed over.

A uranium mine and mill have been inaugurated by Iranian president Mahmoud Ahmedinejad as the country celebrates National Nuclear Technology Day.

Iran has continued to develop its uranium enrichment capabilities, including the installation of more centrifuges at both the Fordow and Natanz sites, the International Atomic Energy Agency reported.