BOGOTA, Colombia – Suspected rebels dynamited four energy pylons yesterday, leaving more than 2.3 million people in southwestern Colombia without electricity.

Energy officials were scrambling to find a temporary fix while the army secured the area so crews could repair the downed towers, Mines and Energy Minister Luis Ernesto Mejia said.

Authorities believe Colombia’s main rebel group, the Revolutionary Armed Forces of Colombia, or FARC, was responsible, an army official said.

The FARC and a smaller guerrilla group have been fighting the Colombian government for four decades. They often blow up energy towers, bridges, oil pipelines, and other infrastructure, aiming to wreak havoc on the economy.

The rebels have de facto control of large parts of the region along the Ecuadorean border where the pylon attacks occurred and in the past few months have launched several deadly assaults on military installations in the area.

More than 18,000 of the 165-foot-tall electrical towers dot Colombia’s vast and mountainous territory, making them an easy target. Rebels blew up 121 towers last year, down from an all-time high of 483 in 2002, according to the government.

Other attacks have not caused widespread power outages, but yesterday’s sabotage hit key pylons linked to large circuits, a spokesman for state-controlled electric company, ISA, Gabriel Gallon, said.