Ahmadinejad said that in order to generate 20,000 megawatts of electricity, Iran would need 500,000 centrifuges of the current model being used in Natanz, Iran's largest nuclear enrichment plant.

"We should reach a position where we can produce from 250-300 tonnes of nuclear fuel a year. To do this we must employ new centrifuges with a higher speed," Ahmadinejad said.

'Serious violation'

The decision comes only two days after the International Atomic Energy Agency (IAEA), the UN nuclear watchdog, censured Iran over its nuclear programme and called on Tehran to halt the construction of a newly revealed enrichment facility near the city of Qom.

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The Iranian announcement drew strong condemnation from Washington with the White House condemning "yet another serious violation of Iran's clear obligations under multiple UN security council resolutions".

In a statement Robert Gibbs, the White House press secretary, said that if construction of the new plants went ahead it would be "another example of Iran choosing to isolate itself".

"The international community has made clear that Iran has rights, but with those rights come responsibilities," Gibbs said.

"As the overwhelming IAEA board of governors vote made clear, time is running out for Iran to address the international community's growing concerns about its nuclear programme."

Alireza Ronaghi, Al Jazeera's correspondent in Iran, said the latest announcement from Tehran was a very clear reaction to the IAEA resolution.

"The head of Iran's atomic organisation said that Iran didn't have any plans to have any more nuclear enrichment facilities, but the resolution forced them to make this decision.

"He also said that the new enrichment facilities will ... be built in the mountains - safe from possible strikes by air, or any other kind of threat.

"Right now I don't think that ratcheting up the rhetoric against Iran will help. Both Iran and the international community are moving towards a place where there will be no more space left for reconciliation," Ronaghi said.

Reduce ties

Iranian MPs responded angrily to the resolution by demanding that Ahmadinejad's government reduce ties with the IAEA.

"We consider the behaviour of the IAEA to be that of double standards and political. We want it to give up this double standard which has tarnished its reputation," the MPs said in a statement on Friday.

Western powers, including the US, accuse Iran of covertly seeking to develop atomic weapons. They demand that Iran accept a UN brokered offer that would delay Iran's ability to make a nuclear weapon as well as engage in broader talks with the ultimate goal of persuading it to stop its enrichment programme.

Iran has amassed about 1,500 kilogrammes of low-enriched uranium at Natanz but Tehran insists it is for civilian purposes.

The UN offer aims to convince Iran to hand over more than 1,200 kilogrammes, more than the commonly accepted amount needed to produce weapons-grade material.

Iran has rejected the UN terms for the plan.

The decision to build more enrichment plants will aggravate tensions between the Islamic Republic and major powers seeking a diplomatic solution to the long-running dispute over Iranian nuclear work.