The top US military commander in the Middle East says violence in Afghanistan has reached its highest level since the US-led invasion of 2001. General David Petraeus said the attacks hit a more than seven-year high last week. Addressing the public outrage in Afghanistan over scores of deadly US attacks, Petraeus said, “This is the graveyard of empires…It is a place that has never taken kindly to would-be conquerors.”