Tehran on Friday invited Western nations to participate in the construction of nuclear power plants across Iran, in the latest round of the country reiterating its tough stance on a disputed nuclear issue. The invitation would test the West's "good will" and restore Iran's trust in the West, shaken after the years of the country's suspension of nuclear activities, Vice President Gholam Reza Aghazadeh said. It comes after Iran announced on Monday an international bid for the building of two more nuclear power plants, despite international pressures to curb its controversial program. Tehran says the plants would be light-water reactors, each with the capacity to generate up to 1,600 megawatts of electricity and would cost up to US$1.7 billion (â‚¬1.25 billion) and take up to 11 years to construct. It was not immediately known if there were responses to the bid. "The international tender for construction of the two nuclear power plants ... is a good yardstick to test the Westerners' good will," Aghazadeh told the official IRNA news agency but did not mention any specific country. Aghazadeh said that Iran will never again stop uranium enrichment and vowed that Tehran will continue to work around the clock to install more centrifuges at its underground enrichment plant in Natanz, until all 50,000 planned centrifuges are in place, IRNA reported. Aghazadeh claimed that Iran showed "good will" when it suspended uranium enrichment in 2003 for three years, but later lost trust in Western nations after learning they were "seeking a permanent halt to Iran's nuclear activities" rather than guarantees the program would not be diverted to weapons making. "Therefore, we won't repeat this experience," he said of the possibility of another suspension. Aghazadeh insisted Iran has upgraded uranium enrichment to an industrial scale but prefers not to get into a dispute over the number of centrifuges. The UN nuclear agency monitors who inspect Natanz would see this for themselves, he said. "Each month, IAEA inspectors will see considerable changes in relation to installation of centrifuges in Natanz," said Aghazadeh. "The infrastructure in Natanz will not only house several thousand centrifuges but is geared to set up an entire nuclear fuel production factory ... involving 50,000 underground centrifuges." The enrichment process can produce fuel for nuclear reactors or, if taken to a higher degree, the material for atomic bombs. Iran says it wants to enrich uranium only to lower levels suitable to generate nuclear power. The UN Security Council last month voted to impose new sanctions on Iran as part of a second set of penalties in three months against Tehran over its refusal to suspend enrichment. Aghazadeh also said Iran will inaugurate a plant producing nuclear fuel pellets within a year. The pellets are the processed form of enriched uranium and serve as fuel in reactors.