Hooded men in uniforms without insignias killed 12 members of the Awa indigenous group, including five children, on a reserve in a region plagued by the cocaine trade, authorities said.
Indigenous leaders said the killings took place on Wednesday at 5 am (local time) on the Gran Rosario reserve about 80 km inland from the Pacific port of Tumaco. The reserve has about 1,500 Awa.
The state governor, Antonio Navarro, said that the victims were all related. The attack killed five men, two women, two boys, two girls and a baby. He said two males, a 10-year-old and a 20-year-old, were wounded in the gunfire but fled and survived.
The identity of the killers was not immediately known.
In February, Revolutionary Armed Forces of Colombia rebels acknowledged killing eight Awa Indians at a different but nearby reservation for allegedly working as informants for the army.
The area is rife with coca plantations and illegal armed groups — leftist rebels as well as far-right militias — that process the leaf into cocaine and smuggle it out of Colombia, typically down rivers that are the region’s main highways.
Mr. Navarro said he could not remember a massacre of so many people in Narino state. He said the survivors described the killers as tall, fair-haired men with moustaches, ruling out local Indians.