Police check students' backpacks during the Safe Backpack Operation at a school in Mexico City, capital of Mexico, on Jan. 19, 2017. Safe Backpack Operation has been reinforced since Thursday at 8,000 schools of Mexico City. Mexico's President Enrique Pena Nieto on Thursday called for stricter security measures for schools, a day after a teenage student opened fire in classroom. (Xinhua/Fernando Ramirez)
