Forces from the two large left-wing rebel groups ELN and Farc have been fighting each other in the Catatumbo region in northeastern Colombia, near the border with Venezuela, for about a week.
There has already been a first battle between the army and members of the National Liberation Army ELN. The order is to take over the territory, says Colombia's Defense Minister Ivan Velasques.
Over 9,000 soldiers are now deployed in the area, where battles over cocaine trafficking have been ongoing between rival guerrilla groups for several years.
At least 80 people have been killed in the latest fighting and many have been kidnapped. Tens of thousands of people have been forced to flee, according to government and UN estimates.
