U.S. Attorney General Eric Holder (right) and FBI Director Robert Mueller announce a plot had been foiled involving men allegedly linked to the Iranian government to kill the Saudi ambassador to the U.S. and bomb the embassies of Saudi Arabia and Israel in Washington at a news conference October 11, 2011 in Washington, DC.

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A fireman walks amongst the rubble and the smoldering wreckage of the World Trade Center in New York in the wake of the Sept. 11, 2001, attacks. Gary Friedman/AFP/Getty Images hide caption

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Fire broke out in Kabul's Inter-Continental Hotel on Tuesday during the attack. Massoud Hossaini /AFP/Getty Images hide caption

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An undated file photo provided by U.S. Marshals shows Carlos Eduardo Almonte, left, and Mohamed Mahmood Alessa, right, who were arrested at New York's Kennedy Airport on June 5, 2010. AP hide caption

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Homeland Security Secretary Janet Napolitano testified before the House Committee on Homeland Security today (Feb. 9, 2011). Mandel Ngan/AFP/Getty Images hide caption

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