VIENNA: Iran has frozen the expansion of its nuclear activities, a UN atomic watchdog report said on Thursday. The International Atomic Energy Agency (IAEA) said that in the last three months it saw a decrease in installation of centrifuges in Iran’s Natanz plant and Fordo facility. It added that “no new centrifuges were put into operation.” IAEA also said that Iran has not begun operating any new-generation IR-2M centrifuges and that no major components had been installed at a reactor being built at Arak. IR-2M centrifuges are of concern to the international community because, in theory, they shorten the time needed by Iran to produce enough weapons-grade uranium for a nuclear bomb. The so-called IR-40 reactor at Arak is also a worry because it could provide Iran with plutonium, an alternative to uranium for a nuclear weapon, once it has been up and running for 12 to 18 months.