Fighters from the Islamic State of Iraq and Syria march in Raqaa, Syria, in a picture posted on Jan. 14. The group is believed to hold as much as $2 billion. AP hide caption

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Smoke rises above Jinnah International Airport Monday morning, following a five-hour firefight between security forces and militants. The facility was open for business Monday afternoon. Shakil Adil/AP hide caption

itoggle caption Shakil Adil/AP

A bomb blast and explosions that followed killed more than 70 people and injured more than 120 on Monday near Nigeria's capital, Abuja. Early speculation is that the attack was the work of the Boko Haram extremist group. /EPA/Landov hide caption

itoggle caption /EPA/Landov

Pakistani security personnel examine the site of a suicide bombing in the Ibrahimzai area of Hangu, Pakistan, on Monday. The bombing killed 15-year-old Aitizaz Hasan, who prevented the bomber from attacking a school. Basit Shah/AFP/Getty Images hide caption

itoggle caption Basit Shah/AFP/Getty Images

A woman wiped away tears Monday in Volgograd, Russia, after the second suicide bombing in that city in the past two days. Denis Tyrin/AP hide caption

itoggle caption Denis Tyrin/AP