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The United States voiced renewed concern Thursday about Iran's nuclear program after a report by the UN's atomic watchdog suggested Tehran may be working on a nuclear warhead.
"We have ongoing concerns about Iran's activities. We cannot explain why it refuses to come to the table and engage constructively to answer the questions that have been raised," State Department spokesman P.J. Crowley told reporters.
The Vienna-based International Atomic Energy Agency (IAEA) said earlier Thursday in a restricted report obtained by AFP that Tehran may be working on a nuclear warhead and had begun enriching uranium at higher levels.
