An explosive device killed 13 people travelling on a bus in southwestern Colombia on Saturday, an attack the country’s army chief described as a “terrorist act” that also left at least 38 injured as violence linked to drug trafficking in the region escalates. Octavio Guzman, the governor of the region of Cauca, said on social media that the device was set off while the bus was travelling along the Panamerican Highway in the municipality of Cajibio. Five children were among the injured, Cauca...