A man rides in a donkey cart past Kenya policemen as he crosses from Kenya into Somalia at the border town of Mandera December 5, 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 TPX IMAGES OF THE DAY)