The army said troops backed by planes and helicopters captured a camp belonging to the ELN - the smaller of Colombia's two guerrilla groups.
The fighting occurred near Saravena, in the eastern Arauca region.
It came a day after the authorities confirmed that 14 policemen had been killed in an ambush in the southern region of Caqueta.
A police convoy was hit by roadside bombs and gunfire, leaving some officers trapped inside a burning vehicle.
Read more here.
Semana International delivers news about Colombia in English. Find more in our home.