The deadly attack occurred in in Colombia's Cauca state as residents were preparing for a farmer's market. Police Major General Jorge Nieto said the attackers used "cylinders camouflaged by food items inside of a vehicle."
No one has claimed responsibility for the attack, which also injured three soldiers, twelve police, and twenty-three civilians.
President Santos was in Washington, D.C. last week to meet with President Barack Obama.
Notable deaths of 2014 [PHOTOS]