The Awa have been the target of previous attacks
Twelve members of an indigenous tribe have been massacred by armed men in a Colombian area notorious for its cocaine trade, state authorities say.
Five children were among those killed in the dawn attack by hooded men in uniforms at an Indian reservation in the south-west province of Narino.
Officials said a man and a boy were wounded in the shooting but escaped.
Marxist rebels and armed right-wing groups are active in the area, home to large numbers of coca plantations.
The armed men shot the members of a family in two houses in the Gran Rosario reserve, about 80km (50 miles) inland from the port of Tumaco in Narino state.
Narino Governor Antonio Navarro told BBC Mundo the victims were seven adults and five children.
About 1,500 members of the Awa live on the reservation.
The identities of the killers, who were said to be wearing uniforms without insignias, are unknown.
The state and central governments have offered rewards for information leading to their arrests.
"We know they were hitmen, but we don't know who hired them, whether paramilitaries, the Farc, or some other group linked to the security forces," Luis Evelis Andrade, the head of Colombia's National Indigenous Organisation told the BBC.
Earlier this year 17 Awa people were killed in an attack blamed on Farc rebels, with 10 others being murdered a week later.
However, Mr Navarro said that unlike in February, the reports they were were evaluating did not point to the guerrillas as being behind the latest killing.
The United Indigenous Awa People's Organisation (Unipa) said that among those killed was a woman, Tulia Garcia, who had witnessed her husband's murder in May.
Despite repeated death threats, she had continued to denounce his murder, Unipa said in a statement.
Colombian President Alvaro Uribe deplored the latest violence.
"It pains us to the core," he said after holding a meeting to discuss the killings.
Mr Uribe said the Office of the UN Human Rights Commissioner had been asked, and had accepted, an invitation to follow the investigations into the massacre.
Unipa said that of the 77 indigenous people killed this year in Colombia, 38 were Awa.
"It is unbelievable that despite the presence and intervention of national and international organisations and institutions, armed attackers continue to violate the fundamental rights, international humanitarian rights and the basic conditions of life of our communities," Unipa said.
Indigenous people in Narino, as in many parts of Colombia, find themselves on the front line of the 45-year civil conflict, as their land often sits on important transport routes where coca and poppy crops are grown as part of the cocaine and heroin trade.