Students demonstrators take cover from tear gas during a protest supporting an agriculture nation wide strike in Bogota

Students demonstrators take cover from tear gas during a protest supporting an agriculture nation wide strike in Bogota April 28, 2014. Farmers across Colombia began protests on Monday demanding the government enact reforms it promised last year, organizers said, in demonstrations that could unsettle President Juan Manuel Santos as he runs for re-election in four weeks. REUTERS/John Vizcaino (COLOMBIA - Tags: CIVIL UNREST AGRICULTURE POLITICS)