Six soldiers were killed Monday in an attack by Revolutionary Armed Forces of Colombia (FARC) guerrillas in southern Colombia, military sources said.
The guerrillas hurled grenades and fired automatic rifles as they attacked an army patrol in a rural area of Cauca department south of Bogota, a source with the army's 29th Brigade told AFP.
The rebels killed five soldiers and a non-commissioned officer, the source said, adding that there were no injured reported.
The army was investigating the circumstances surrounding the attack, which was believed to have been carried out by the FARC's Jacobo Arenas column.
The attack came just days after the FARC released six hostages to a peace group led by Senator Piedad Cordoba.
In a statement, the FARC said it hoped that the release would unblock stalled talks aimed at completing a hostages-for-prisoners swap.
The rebels are holding hundreds of hostages, including 22 military and police that they are seeking to swap for some 500 guerrillas held in Colombian and US jails.
"All of Colombia wants to celebrate through an... agreement on the release of prisoners of war held both in the regime's jails and in the mountains," read the statement, signed by the FARC central command and posted on senator Cordoba's website.
The website also carried a letter from the FARC's top leader, Alfonso Cano, to Cordoba stating that his group met its commitment to release the hostages "despite the obstacles, slanders and official provocations."
With 7,000 to 8,000 fighters, the FARC is the largest guerrilla group operating in Colombia.