Iran is preparing to install advanced machinery at its new uranium enrichment site.
The announcement by the country's nuclear energy chief is another act of defiance by Iran, despite international sanctions over its controversial nuclear programme.
Fereidoun Abbasi said it will soon set up a more advanced type of centrifuge, suitable for higher-level uranium enrichment, at the Fordo site near the holy city of Qom in central Iran.
Fordo was long kept secret. It was built next to a military complex to protect it in case of an attack.