Iran Could Produce Nuclear Bomb in 16 Days, U.S. Says (Update2) April 12 (Bloomberg) -- Iran, defying United Nations Security Council demands to halt its nuclear program, may be capable of making a nuclear bomb within 16 days, a U.S. State Department official said. Iran will move to ``industrial scale'' uranium enrichment involving 54,000 centrifuges at its Natanz plant, the Associated Press quoted deputy nuclear chief Mohammad Saeedi as telling state-run television today. ``Using those 50,000 centrifuges they could produce enough highly enriched uranium for a nuclear weapon in 16 days,'' Stephen Rademaker, U.S. Assistant Secretary of State for International Security and Nonproliferation, told reporters today in Moscow. Rademaker was reacting to a statement by Iranian President Mahmoud Ahmadinejad, who said yesterday the country had succeeded in enriching uranium on a small scale for the first time, using 164 centrifuges. That announcement defies demands by the UN Security Council that Iran shut down its nuclear program this month. The U.S. fears Iran is pursuing a nuclear program to make weapons, while Iran says it is intent on purely civilian purposes, to provide energy. Saeedi said 54,000 centrifuges will be able to enrich uranium to provide fuel for a 1,000-megawat nuclear power plant similar to the one Russia is finishing in southern Iran, AP reported. ``It was a deeply disappointing announcement,'' Rademaker said of Ahmadinejad's statement. Weapons-Grade Uranium Rademaker said the technology to enrich uranium to a low level could also be used to make weapons-grade uranium, saying that it would take a little over 13 years to produce enough highly enriched uranium for a nuclear weapon with the 164 centrifuges currently in use. The process involves placing uranium hexafluoride gas in a series of rotating drums or cylinders known as centrifuges that run at high speeds to extract weapons grade uranium. Iran has informed the Vienna-based International Atomic Energy Agency that it plans to construct 3,000 centrifuges at Natanz next year, Rademaker said. ``We calculate that a 3,000-machine cascade could produce enough uranium to build a nuclear weapon within 271 days,'' he said. While the U.S. has concerns over Iran's nuclear program, Rademaker said ``there certainly has been no decision on the part of my government'' to use force if Iran refuses to obey the UN Security Council demand that it shuts down its nuclear program. Rademaker is in Moscow for a meeting of his counterparts from the Group of Eight wealthy industrialized countries. Russia chairs the G-8 this year. China is concerned about Iran's decision to accelerate uranium enrichment and wants the government in Tehran to heed international criticism of the move, Wang Guangya, China's ambassador to the United Nations said.