New South Wales Police Commissioner Andrew Scipione (right) and Australian Federal Police Acting Commissioner Andrew Colvin describe how 800 federal and state police officers raided more than two-dozen properties as part of the operation Thursday in Sydney. Rick Rycroft/AP hide caption

itoggle caption Rick Rycroft/AP

Syrian rebel fighters in the northern city of Aleppo in August. The Obama administration has been vetting rebel groups and decided that more than a dozen are moderate enough to arm. Zein al-Rifai/AFP/Getty Images hide caption

itoggle caption Zein al-Rifai/AFP/Getty Images