Both the ELN and FARC-EMC have long fought for control over this drug-rich area, but recent violence marks a significant escalation.

Colombian President Gustavo Petro on Friday issued a decree that gives him emergency powers to respond to an outbreak of deadly violence between rival armed groups in the north-eastern Catatumbo region.

Colombia called on neighboring Venezuela Thursday to help tackle guerrillas blamed for a week of bloody violence that has displaced 40,000 people in the lawless border region.