Suspected FARC rebels detonated explosives along a section of an oil pipeline near Colombia's border with Ecuador, the state oil company said Monday.
The attack late Sunday came the same day the Revolutionary Armed Forces of Colombia ended a ceasefire it declared unilaterally two months ago as it began peace talks with the Colombian government in Havana.
A spokesman for Ecopetrol, the state-owned oil company, told AFP that the attack occurred in a section of the Trans-Andean pipeline near the town of Orito in southern Putumayo province.
It caused a small spill but the loss was limited because the line, which carries oil from Ecuador to the Colombian port of Tumaco on the country's Pacific coast, was down for a scheduled maintenance, the spokesman said.
He said repairs would begin once the army had secured the area.
The FARC, Colombia's largest rebel group and Latin America's oldest, has been active in Putumayo for years.
The first peace talks in a decade opened in Havana in November but have yet to find an end the nearly 50 year old conflict.