Colombian troops killed 14 Marxist rebels in heavy fighting, five days before scheduled parliamentary elections.
Another 85 members of the Revolutionary Armed Forces of Colombia (FARC) were captured in the offensive, a military spokesman said on Tuesday.
FARC has killed 75 people in the last two weeks in a series of attacks believed to be aimed at derailing the parliamentary elections scheduled for March 12 and discrediting the government of hard-line President Alvaro Uribe, who will be running for re-election in May.
Colombia has been in a 40-year civil war, in which leftist rebels have been battling the government and rightwing paramilitaries for control of the country.
FARC is the largest of the Marxist guerrilla forces.
Uribe has stepped up efforts to defeat Colombia's leftwing rebels by military force since coming to power in August 2002.