Colombia's army killed 18 members of the leftist rebel group, the Revolutionary Armed Forces of Colombia (FARC) Thursday in a bombing raid, an army official said.
The operation took place in the Cauca region of western Colombia, a FARC stronghold and a key drug trafficking area.
The air strike is one of the deadliest between the guerrillas and the government since peace talks between the two sides started more than two years ago.
Colombian President Juan Manuel Santos lifted an air strike suspension against the Marxist guerrillas last month after members of the rebel group became suspects in the killing of 10 soldiers.
FARC has been fighting the Colombian government since the mid-1960s. The civil conflict has killed more than 200,000 people.