In a sign of how dangerous the situation in Libya has become, the United Nations pulled its staff out of the country on Monday. At least six people died in Benghazi and seven in Tripoli after violence broke out Sunday night. The clashes have also shut down the international airport in Tripoli after several Grad rockets damaged the control tower. The country is suffering from some of its worst violence since the fall of Muammar Gaddafi, and the military appears unable to control rebels