In 1994, Oxy told its shareholders the company had found what it thought was one of the largest oilfields in Latin America. Colombia's Samore oilfield, located in the northeast of the country, was said to contain 1.4 billion barrels of oil with a further 900 million barrels in an adjacent field.

However, the Guardian reported that this month, the $US10 billion-a-year Oxy oil company is now set to leave the region for "technical reasons" despite spending $US100 million on research and seismic studies. The company will also hand back its 2000 sq.km concession to the Colombian Government.

The decision by Oxy to leave the area after only one well is a big victory for the U'wa tribe who, according to a tribal spokesman, exist only "to protect the earth" and threatened mass ritual suicide if the Oxy took the oil.

According to U'wa legend, the world above ground is mirrored by the world below, and oil is the blood of the earth - an element that sustains the land and lakes and prevents earthquakes. Many tribesmen believed the prayers and fasting of their mystical leaders - the werjayas - drove the oil company away.

Instrumental in helping the U'wa tribe fight Oxy was a young American environmentalist, Terry Freitas, who was killed by Colombian guerrillas during his third visit to the tribe in 1999. American human rights and environmental groups subsequently picked up the cause and won major environmental awards for their campaign.

The fight over the Samore field was a major embarrassment for one time Presidential candidate, Al Gore who prided himself on being sympathetic to environmental causes. Mr Gore's grandfather worked with the founder of Oxy, Armand Hammer, while Al himself was a major individual shareholder.

Despite U'wa victory, Colombian state oil company, Ecopetrol, which has assumed control of the concession intends to continue looking for oil.