Iran will begin building its third uranium enrichment plant in early 2011, defying world powers who have imposed new sanctions on Tehran for pursuing the sensitive nuclear work. Iran's atomic chief Ali Akbar Salehi was cited on state television's website late yesterday as saying the search for locations for 10 new enrichment facilities has ended and the construction of one of these facilities will begin by the end of the year or the start of next year. Iran is already enriching uranium at its main plant in the central city of Natanz and is building a second enrichment facility inside a mountain at Fordo, southwest of Tehran. Salehi, who is also one of 12 vice presidents of Iran, has previously said that any new uranium plants the Islamic republic builds would be located at sites which cannot be targeted by air strikes. He did not specify where the third plant would be located.