SHARE

Two contractors working for Colombia’s state owned Ecopetrol were killed Sunday by a leftist guerrilla sniper attack at the Caño Limón Coveñas crude pipeline in northwest Colombia.

The Colombian military said the attack was most likely staged by a group associated with the National Liberation Army (ELN), Reuters said.

The names of the workers have not been released.

ELN is Colombia’s second largest rebel group.

The contractors were attacked while performing maintenance work at a portion of the 478 mile pipeline located in Norte de Santander, a department of Colombia that borders Venezuela.

The sniper was stationed in a house across a river from where the two men were working.

The killings are part of a recent upsurge in attacks against oil infrastructure by the ELN and the Revolutionary Armed Forces of Colombia (FARC).

The attacks have dropped oil production below the government’s target of one million barrels per day.

Colombia’s president Juan Manuel Santos said in June that his administration would negotiate a formal peace process with the ELN but details about the plan have not been disclosed.

In late June, ELN staged an attack in the Arauca department that injured 13 oil workers and their family members after the group set off homemade explosive devices.