Colombian military officials say at least 12 Marxist rebels and two soldiers have been killed in clashes in the southern coca-growing region.
Authorities say the fighting occurred Friday in Meta province, near a national park where rebels last week killed 29 soldiers guarding workers destroying coca crops.
The military has been trying to rid the region of rebels before the government launches a coca plant eradication program later this month.
Colombian President Alvaro Uribe has pledged to increase efforts to destroy the plants used to make cocaine.
Also Friday, Colombian police said they captured a commander of the guerrilla group known as the National Liberation Army, or ELN.
Giovanni Giraldo Carvajal was arrested in Medellin and is believed to have directed rebel operations in Antioquia province.
The ELN and the larger, 17.000-strong force known as the Revolutionary Armed Forces of Colombia, or FARC, have been engaged in a deadly 41-year civil war to topple the government. Some information for this report was provided by AP and Reuters.