At least ten Colombian soldiers were killed on Thursday when leftist guerrillas exploded a bomb as the army patrolled a rural area in the south-west of the country, military officials said.
Local army commander General Hernando Perez told the local Caracol radio station that country's largest rebel group, the Revolutionary Armed Forces of Colombia, known as the FARC, had carried out the attack in Valle del Cauca province.
Two officers and eight soldiers were killed in the attack, an army spokesman said.
The ambush was the second major attack on Colombia's security forces this week. Nine police officers were killed in a FARC bomb ambush on Wednesday in Santander province in the north of the country while on a counter-narcotics operation.