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

itoggle caption Jim Watson/AP

An unmanned U.S. Predator drone flies over Kandahar Air Field in southern Afghanistan on Jan. 31, 2010. Drones have become the U.S. weapon of choice in the fight against terrorism. But as the technology of this new form of warfare improves, so do concerns about how others will use it in the future. Kirsty Wigglesworth/AP hide caption

itoggle caption Kirsty Wigglesworth/AP

Baily the donkey (right) and Munna, characters from the Pakistani version of Sesame Street, perform at the launch ceremony for the show, Sim Sim Hamara, at Rafi Peer Theater Workshop in Lahore, Nov. 26, 2011. Mohsin Raza/Reuters/Landov hide caption

itoggle caption Mohsin Raza/Reuters/Landov

A NATO soldier aims his weapon during a gun battle in Kabul, Afghanistan, in April. NATO is holding a summit in Chicago this weekend, and discussing the future of the alliance is on the agenda. Musadeq Sadeq/AP hide caption

itoggle caption Musadeq Sadeq/AP