Colombia's army claims to have killed 17 guerrillas and captured 114 in the past six days in one of the biggest offensives against Marxist rebels this year.
Two army brigades backed up by helicopters and aircraft aimed "Operation Scorpion" at the "Teofilo Forero" rebel unit, responsible for some of the major attacks by the Revolutionary Armed Forces of Colombia, known as FARC, army spokesmen said.
The military engaged in 26 firefights with the FARC rebels in the offensive, which occurred in the southern province of Caqueta, in the heart of what once was a demilitarised zone set aside for peace talks with the guerrillas.
No soldier was killed or injured, the army said.
The Teofilo Forero used to guard rebel peace negotiators. But it was also partly responsible for the collapse of talks in February 2002, when it hijacked a commercial plane and kidnapped a national senator.
President Alvaro Uribe has boosted defense spending and ordered the military to do more to fight the FARC, a 17,000-strong force funded by cocaine and kidnapping, which is fighting a 39-year-old guerrilla war.
Critics say the military has failed to capture or kill any senior FARC commanders and even the Government has admitted the armed forces have not dealt major blows to the rebels.
Thousands of people, mainly civilian, have been killed in the conflict.