Bogota: Colombia`s FARC guerrillas killed five soldiers Friday in an attack that came on the eve of a unilateral ceasefire hailed as a key step in peace negotiations, the army said.
FARC fighters ambushed a patrol in the rural area of Santander de Quilichao in western Colombia, in a pre-dawn attack that also left five soldiers lightly wounded and one missing, the army said.
The incident came a day before the leftist guerrilla group was due to begin an indefinite, unilateral ceasefire that it declared on Wednesday, a move the European Union and United Nations had praised as a positive step to accelerate the peace talks aimed at ending the 50-year-old conflict.
The Colombian government`s chief negotiator in the talks, Humberto de la Calle, condemned the attack.
"We have to reiterate that the purpose of the talks is for this to stop," he said.
The commander of the brigade whose unit was attacked, General Wilson Chawez, vowed the army would continue fighting the "terrorists."
"We`re going to pursue our military operations. It`s a unilateral ceasefire. We`re an army that remains on the offensive," he told journalists.
The FARC has said that starting Saturday its fighters will only engage in hostilities if they come under attack.
The unprecedented ceasefire declaration had raised hopes of a new breakthrough in the peace process.
The FARC had declared Christmas ceasefires for the past two years, but this is the first to be offered without an expiration date.
On Thursday, Colombian President Juan Manuel Santos called the gesture a "gift... full of thorns" and again rejected the rebels` longstanding demand for a bilateral ceasefire, which he says they would use to regroup.
Friday`s attack is the latest blow to the two-year-old peace talks being held in Cuba, which have encountered rocky terrain in recent weeks.
Last month, the FARC captured an army general who headed an anti-rebel task force in the jungle-covered region of Choco, their highest-ranking captive ever.
The incident caused Santos to suspended the peace negotiations, which he has made the centerpiece of his administration despite fierce criticism from the opposition.
The FARC defended their capture of the general as a legitimate act of war in the absence of a ceasefire, but released him on November 30 in order to revive the stalled peace process.
The talks, which opened in November 2012, are the most promising effort yet to end the five-decade guerrilla war, which has defied three previous attempts.
The conflict has killed 220,000 people and uprooted more than five million, according to the government.
It has drawn in multiple leftist rebel groups, right-wing paramilitaries and drug gangs at various times since the Revolutionary Armed Forces of Colombia (FARC) was founded in the aftermath of a peasant uprising in 1964.