The blast before dawn unleashed a ball of fire that ripped through the town of Dosquebradas. Authorities said they were investigating what caused the explosion and suspected it was set off by thieves who may have tapped the pipeline to steal fuel.
Eight people died near the explosion and three others died later at hospitals, said town official Oscar Andres Herrera. He said 88 people were injured, at least five of them severely burned.
President Juan Manuel Santos visited the site of the explosion and promised government assistance to the victims and their families. He said the cause remained unclear but that authorities suspected thieves were to blame.
The explosion sparked a fire that was extinguished Friday morning. The blast and flames destroyed 25 homes and damaged 47 others, Herrera said by phone.
The pipeline, which carries gasoline and diesel, is operated by national oil company Ecopetrol.
The explosion occurred in the central province of Risaralda, located about 100 miles (170 kilometres) southwest of the capital of Bogota.
Officials suspect that thieves had been trying to remove fuel through one of the valves in the pipeline, Mines and Energy Minister Mauricio Cardenas said. Cardenas later told reporters at the blast site that officials were investigating to pinpoint the cause.
Images on Colombian television showed some of the houses destroyed by the blast and other homes with charred walls. The waters of a nearby stream were flaming with some of the spilled fuel.
Police officer Juan Pablo Munoz, who works elsewhere in the country but was visiting family for Christmas, said he was jolted out of bed by the explosion.
"I smelled a strong odour of gasoline," the 21-year-old said by phone. "I went out into the street. I walked at least 10 steps and I saw that everything around me was destroyed."