TEHRAN Iran has begun installing 6,000 new centrifuges at its uranium enrichment plant, President Mahmoud Ahmadinejad said on Tuesday, defying the West which fears Tehran is trying to build nuclear bombs.
The United States said the move showed once again that Tehran intended to ignore U.N. Security Council demands to halt sensitive nuclear work and France suggested major powers may have to toughen sanctions on the Islamic Republic.
The Security Council has imposed three rounds of limited sanctions since 2006 on Iran for refusing to stop enriching uranium, which can be used as fuel in power plants or provide material for nuclear weapons if refined much further.
Iran, the world's fourth largest oil exporter, says it wants nuclear power to generate electricity to meet booming demand.
"Today we have started the installation of 6,000 new centrifuges," the official IRNA news agency quoted Ahmadinejad as saying during a visit to Natanz in central Iran.
He later told a televised event to mark Iran's National Day of Nuclear Technology that Tehran had defeated its Western foes.
"They imagined that by imposing political pressure and sanctions, Iran's economy will fall apart but we saw that this did not happen."
U.S. Secretary of State Condoleezza Rice said incentives offered to Iran in 2006 if it halted uranium enrichment, including civil nuclear cooperation, had been "very generous."
"Iran faces the continued isolation in the international community because it will not take a reasonable offer from the international community," she said in Washington.
But Foreign Minister Sergei Lavrov of Russia, which is building Iran's first nuclear power plant, told Ekho Moskvy radio that "new positive proposals" should be put to Iran, without specifying what they might be.
The United States, Britain, France, Germany, Russia and China issued a joint statement last month saying they were ready to "further develop" the package of incentives offered to Iran in 2006 if Tehran halts enrichment.
The United States has not ruled out military action to stop Iran's nuclear activities and Israeli government spokesman Mark Regev urged the international community to stop Tehran's "aggressive" atomic work.
Iran launched 3,000 centrifuges, a basis for industrial scale enrichment, in the underground Natanz production hall last year. But they are a 1970s-vintage design prone to breakdown.
A senior Iranian nuclear official told Reuters Ahmadinejad had also inspected a "new generation" of centrifuges built by Iranian scientists at a research facility at Natanz.
Diplomats in Vienna said last week that Iran was installing advanced enrichment centrifuges at the underground Natanz facility, accelerating activity that could give Tehran the means to make atom bombs in the future if it chose to.
Ahmadinejad said a machine with greater capacity was tested at Natanz on Tuesday: "The capacity of these new machines ... is five times greater than the current machines." A senior official said the president was referring to the advanced centrifuges.
Centrifuges are machines that can spin compounds of uranium at supersonic speed to separate out and concentrate the most radioactive isotope of the element.
Nuclear analysts say around 1,500 such machines would be needed for Iran to manufacture the minimum amount of highly enriched uranium needed for one crude warhead.
The five permanent members of the U.N. Security Council and Germany plan to meet in Shanghai on April 16 to discuss whether to sweeten their 2006 offer of incentives to persuade Iran to curb its nuclear program, a Western diplomat told Reuters.
Iran has ruled out halting or limiting its nuclear work in exchange for trade and other incentives, and says it will only negotiate with the U.N. nuclear watchdog.
France said major powers may need to tighten U.N. sanctions against Iran if it continues to ignore their demands.
"I fear that we will have to continue on the path of sanctions if we do not receive a response from the Iranians," French Foreign Minister Bernard Kouchner said in Paris.
(Additional reporting by Zahra Hosseinian, Hashem Kalantari and Fredrik Dahl in Tehran, Francois Murphy in Paris, Adrian Croft in London, Karin Strohecker in Vienna, Oleg Shchedrov in Moscow, Louis Charbonneau at the U.N. and by Washington bureau; Writing by Parisa Hafezi; Editing by Richard Williams)