He said while the administration had not ruled out military action to curb Iran's nuclear ambitions, the United States was committed first to a diplomatic solution on the issue.
The article by Seymour Hersh made three claims: U.S. clandestine activities inside Iran have increased, planning for a possible air attack has intensified and the option of using of tactical nuclear weapons to ensure the destruction of well-protected Iranian nuclear facilities is still on the table.
In London, British Foreign Secretary Jack Straw said such allegations were "completely nuts."
But in an interview with the BBC, Hersh said there were also questions about how much information the U.S. government was sharing with its European allies.
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