At least 11 leftist rebels were killed in military operations on Colombia's border with Peru, the army said on Tuesday.
The rebels were suspected dissidents from the former Revolutionary Armed Forces of Colombia (FARC) who the government alleged were involved in drug trafficking.
An additional four guerrillas "were injured during fighting" and arrested in the operation, which local media said took place Monday.
Colombia's army, air force and prosecutor's office took part in the operation which occurred in Puerto Leguizamo in the southern Putumayo department.
General Alberto Rodriguez said the rebels were involved in drug trafficking.
The Putumayo department is one of the largest illegal coca leaf growing areas in Colombia, the world's main producer of cocaine.
The FARC dissidents are battling for control of territory and drug-trafficking routes with the National Liberation Army, the last recognized rebel group in Colombia.
The FARC laid down arms and signed a peace deal with the state in 2016 following a half century of armed insurrection.
The dead guerrillas were allegedly from the Segunda Marquetalia FARC dissidents group, which is led by Ivan Marquez, who used to be one of the rebels' lead negotiators in peace talks.
Colombian authorities claim Marquez is hiding in Venezuela under the protection of the oil-rich country's authoritarian President Nicolas Maduro, who denies the accusation.
Colombia President Ivan Duque, a harsh critic of the peace deal signed under his predecessor Juan Manuel Santos, has taken the fight to dissident guerrillas.
In February, 23 dissidents operating in Arauca on the border with Venezuela were killed in another military operation.