At least five soldiers were killed and six others injured in an attack by guerrillas from the National Liberation Army (ELN) in a rural area of the Colombian municipality of Arauquita in Arauca department.
According to officials, the wounded men were promptly transferred to a health centre, where they are recovering from their injuries, while the army "is coordinating the corresponding legal procedures with the relevant authorities", reports Xinhua news agency
"The soldiers of Colombia express their heartfelt condolences to the families, friends, and colleagues of our murdered heroes," said the Colombian Army.
President Ivan Duque condemned the attack, saying on Twitter on Saturday: "These cowardly acts are the product of despair in the face of military pressure. For the memory of our heroes, we will continue attacking narco-terrorism and dismantling its structures."
The ELN is a revolutionary left-wing armed group involved in the continuing Colombian conflict, which has existed in the country since 1964.
The group has been classified as a terrorist organisation by the governments of Colombia, the US, Canada, the European Union and Venezuela's National Assembly.