The Islamic republic has installed 1,000 second generation (IR-2m) centrifuges in one of its nuclear enrichment sites, Head of the Atomic Energy Organization of Iran (AEOI) Ali-Akbar Salehi was quoted as saying by local media on Sunday. However, in light of its ongoing talks with six world powers on its nuclear issue, Iran has not inject UF6 gas into the centrifuges, Salehi said according to semi-official ISNA news agency. "We will not install any more second generation centrifuges since they need required space and infrastructure," he said. "The third and fourth generation centrifuges are going through tests," he said, adding that "there is nothing impossible for Iran in producing these new generation centrifuges." On Friday, Salehi said Iran had 19,000 centrifuges and was developing a new generation of centrifuges which needed all kinds of tests before operation. Iran was among the countries that were able to implement the full process of nuclear fuel production cycle, he said. In November, Iran and the six world powers signed an interim deal, under which Iran agreed not to operate its new centrifuges for six months. The deal, however, does not require the Islamic republic to stop developing new centrifuges. In August, former AEOI chief Fereidoon Abbasi announced that Iran had about 18,000 centrifuges, 10,000 of which were operating. "Iran has 17,000 first-generation (IR-1) centrifuges, out of which 10,000 are running and over 1,000 indigenously manufactured new generation centrifuges (IR-2m) have also been installed and are ready to be launched." Salehi, who is also Iran's vice president, said Sunday that Tehran and Moscow are discussing the construction of four nuclear power plants in Iran, according to ISNA.