Iran will start building a new uranium enrichment plant early next year, the country's top nuclear official says.
The plant is one of 10 new uranium enrichment facilities Iran has said it is planning.
Vice-President Ali Akbar Salehi said Iran has now found sites for all the new plants.
Western powers say Iran is trying to build a nuclear weapon. Iran denies this and says its nuclear programme is for peaceful purposes.
The BBC's John Leyne reports from Cairo that the plan is a gesture of defiance to those outside Iran who fear that the new plants could be used to make nuclear weapons.
The Islamic republic is already enriching uranium at a plant in Natanz in central Iran, and has been building a second enrichment site near Qom, further to the north.
Ali Akbar Salehi, head of Iran's nuclear programme, told state television that "studies on finding locations for the construction of 10 new sites are going through their final stages".
He added that construction would begin on one of these "by the end of the current Iranian year (in March 2011), or shortly afterwards."
The UN and the EU have passed several rounds of sanctions against Iran in an effort to curb the country's nuclear ambitions.
Iran says it needs the plants to supply fuel for a new generation of up to 20 nuclear reactors, the BBC's Jon Leyne says.
However, the only reactor under construction, at Bushehr, is being supplied with fuel by Russia.
Iranian President Mahmoud Ahmadinejad originally announced plans to build the 10 new plants in late 2009, days after the UN nuclear watchdog rebuked Iran for covering up the uranium enrichment plant it was building near Qom.