Colombian warplanes launched pre-dawn air strikes on an encampment in Meta state on Monday, killing 36 people who officials identified as members of the country's main guerrilla force.
President Juan Manuel Santos's right-wing administration launched the bombing raid in the municipality of Vista Hermosa, a traditional stronghold of the Revolutionary Armed Forces of Colombia (Farc), just as the group says it is preparing to free its last prisoners.
Colombian armed forces chief General Alejandro Navas dismissed suggestions that the military attack dubbed Operation Sword and Honour could delay the releases, saying the strikes fell within the "rules of the conflict."
Gen Navas said Monday's blitz had been planned for several months and had targeted the Abelardo Romero Column in Farc's 54th Front.
Commandos captured five guerillas, including three women, and seized weapons and computers, the military high command said.
Last week, the military killed 33 rebels in a similar air raid on another Farc stronghold, in Arauca state near the border with Venezuela.
Although Colombia's military brass has been tight-lipped on operational details, the attacks follow a new strategy devised after they tracked down and killed Farc's previous commander Alfonso Cano last year.
Colombia's modernised military and billions of dollars of US aid have increasingly battered Farc, who were seeking peace talks even before Mr Cano's death.
Farc has said it plans to release its last prisoners, 10 soldiers and police officers held for as long as 14 years, on April 2 and 4.
Guatemalan Nobel Peace Prize laureate Rigoberta Menchu has announced that she will mediate the release along with former Colombian senator Piedad Cordoba of the Colombians for Peace group.
A delegation is set to go to Brazil on Saturday to meet Brazilian air force personnel in charge of providing helicopters and personnel for the hostage release.
Farc recently announced a halt to ransom kidnappings that have been a financing tool, yet it continues to mount military operations.
The government launched the March 21 raid in Arauca four days after guerillas in the same region killed 11 soldiers in an ambush.
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