A man looks out of a bus as it travels to Nairobi, next a police vehicle escorting it through Mandera town, at the Kenya-Somalia border, December 6, 2014. Somali al Shabaab Islamist militants killed 36 non-Muslim workers at a quarry in Mandera, northeast Kenya on Tuesday, prompting the president to sweep out his top security officials in order to tackle a relentless wave of violence. REUTERS/Goran Tomasevic (KENYA - Tags: CIVIL UNREST SOCIETY TPX IMAGES OF THE DAY)