The FBI is investigating more than 100 suspected Muslim extremists who are part of the U.S. military community, officials tell NPR. U.S. authorities have increased scrutiny since the 2009 shooting attack at Fort Hood, Texas, that left 13 dead. Maj. Nidal Hasan, charged with the killings, is shown here in an April 2010 court hearing. Handout/Getty Images hide caption

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Some parents say the hardest part of flying with young kids on an airplane is dealing with unpredictable kids and adult passengers. iStockphoto.com hide caption

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President Obama's use of drones, and his direct involvement in whom they target, has both U.S. and international communities questioning the administration's secret drone policy. Kirsty Wigglesworth/AP hide caption

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This undated photo of Francis Gary Powers shows him standing next to a U-2 spy plane. Powers was shot down and captured in the Soviet Union in 1960 and held for nearly two years. He was posthumously awarded a Silver Star at the Pentagon on June 15. AP/Allied Museum hide caption

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President Richard Nixon tells reporters he will not allow his legal counsel, John Dean, to testify before Congress in the Watergate investigation, March 15, 1973. Leaks about the Watergate break-in eventually helped lead to Nixon's resignation. And his administration fought and lost a Supreme Court battle over leaking of the so-called Pentagon Papers about Vietnam. Charles Tasnadi/AP hide caption

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U.S. Defense Secretary Leon Panetta, shown speaking in India last week, said the U.S. was "reaching the limits of [its] patience" with Pakistan. He is one of several U.S. officials to deliver sharp public criticism of Pakistan recently. Jim Watson/AP hide caption

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