“The uranium enrichment plant in Natanz (central Iran) has been constructed for establishing a factory for 50,000 centrifuges, but it would take between two to four years for install all these centrifuges,” Aqazadeh told ISNA news agency.

Aqazadeh, who is also vice-president, proclaimed last week that Iran has developed the ability to enrich uranium on an industrial scale but refrained to give the exact number of the running centrifuges in Natantz.

“Disclosing the number of the centrifuges is internationally not common,” he said while again refraining to give further details.

There have been indications by Iranian officials that about 3,000 centrifuges were already running in Natanz but several relevant circles, including the International Atomic Energy Agency (IAEA), have voiced doubts about the Iranian claim.

The five-day inspection results of an IAEA team would clarify whether the Iranian claim of 3,000 centrifuges was correct or not.

The IAEA report is to be presented to the UN Security Council and the IAEA board members ahead of its regular meeting scheduled for June 11.

Aqazadeh however said that the IAEA was not authorised to disclose the details of Iran’s nuclear programmes.

According to the IAEA, up to now only the installation of around 1,000 centrifuges - in six so-called cascades with 164 centrifuges each - could be confirmed, although it was still unclear whether all six cascades were fully operational.

Aqazadeh confirmed press reports that some of the centrifuges blew up during the enrichment process. Without giving a precise number of the blown up centrifuges, he said that the damages ranged from ten to twenty per cent.

The atomic chief further claimed that all centrifuges were made in and by Iran adding that imported centrifuges would not be usable in Natanz.

Aqazadeh reiterated that Iran would still prefer to settle the nuclear dispute and remove international concern through negotiations with the five permanent United Nations Security Council members plus Germany.

“We do not want to close our doors to the world and prefer more international understanding, but if they imposed sanctions against us, then we would still be able to manage the country,” he said.

Aqazadeh said that Iran would continue its nuclear programmes despite international pressure “but Iran had no interest in leaving the Non-Proliferation Treaty (NPT).”

Following last December’s UN resolution 1747 and probable sanctions if Iran did not follow the 60-day UN ultimatum for suspending enrichment, the Iranian parliament obliged the government to limit cooperation with the IAEA.

Some local hard-line circles in Iran have even called on withdrawal from NPT but the government has so far refused to do so.

Iran has several times called for the resumption of the negotiations and for a diplomatic settlement to be found for the nuclear dispute but rejected any pre-conditions, especially enrichment suspension.