An explosion has ripped through an oil pipeline in western Colombia, killing 11 people and injuring at least 70 others.

Authorities say the explosion occurred early Friday in the region of Risaralda, west of the Colombian capital, Bogota. A fire that erupted following the blast was brought under control.

The cause of the oil pipeline blast is under investigation and there are conflicting reports as to whether fuel thieves are to blame.

Colombian President Juan Manuel Santos described the explosion as a “great tragedy.” He also expressed solidarity with the victims of the blast, which destroyed or damaged dozens of homes.

Colombia's national oil company, Ecopetrol, operates the pipeline.