Iran said Monday it is currently installing 3,000 centrifuges, effectively confirming that its nuclear program is running behind schedule as these devices for uranium enrichment were to have been in place by the end of last year.

"We are moving toward the production of nuclear fuel, which requires 3,000 centrifuges and more than this figure," government spokesman Gholamhossein Elham told a news conference. "This program is being carried out and moving toward completion."

On the weekend, Iran dismissed reports from Europe that its uranium enrichment program had been stalled. Enriched uranium is used as fuel in nuclear reactor and, at a higher degree of enrichment, it is also used in atomic bombs.

But last year Iran had said the installation of the 3,000 centrifuges at its facility in Natanz, located in central Iran, would be completed by the end of 2006.

The United States and some of its allies accuse Iran of trying to produce atomic weapons. Iran denies this, saying its program is only for generating electricity.

Iran's failure to instal the 3,000 centrifuges by Dec. 31 has provoked reports that it is encountering technical difficulties in mastering large-scale enrichment.

Further, earlier this month, Vice President Gholamreza Aghazadeh, who heads the Atomic Energy Organization of Iran, told reporters that about 50 centrifuges had exploded during a test.

"We had installed 50 centrifuges. One night, I was informed that all the 50 centrifuges had exploded ... (President Mahmoud) Ahmadinejad called me and said: 'Build these machines even if they explode 10 times more,"' Aghazadeh was quoted as saying by Iranian media.

Diplomats in Vienna — where the International Atomic Energy Agency is based — said Thursday that the enrichment program in Natanz had ground to a halt.

Last month President Ahmadinejad boasted that Iran would soon celebrate, probably in February, the completion of its nuclear fuel cycle — the processing of uranium from mining the ore to enriching it.

The government has condemned as "invalid" and "illegal" the U.N. Security Council resolution that imposed sanctions on Iran last month for its refusal to halt uranium enrichment.

The resolution warned Iran that if it refused to comply within 60 days, the council would adopt further sanctions.

Iran says that as a signatory to the Nuclear Nonproliferation Treaty, it has the right to develop a peaceful uranium enrichment program to produce nuclear power.

The International Atomic Energy Agency has said it has found no evidence that Iran is trying to build nuclear bombs, but it has criticized the country for concealing certain nuclear activities and failing to answer questions about the program.

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