Colombia's leftist FARC rebels killed five police officers and injured three others Monday in an ambush in the north of the country, authorities said.
The rebels targeted an anti-narcotics patrol working on coca eradication in Antioquia province, Colonel Fernando Restrepo told AFP.
"This was an intense attack against the units," Restrepo said.
The wounded were taken to area hospitals for treatment.
Defense Minister Juan Carlos Pinzon called the attack an "inexplicable act of barbarity."
"Let us not be fooled in Colombia," he said. "The president's and people's desire for peace and reconciliation is one thing. The desire by these people to trick us with this illegal and criminal trade is another."
Founded in 1964, the Revolutionary Armed Forces of Colombia (FARC) is now estimated to have some 8,000 fighters and is considered the country's largest rebel group.
Since November 2012, the FARC has been in peace talks with the government of President Juan Manuel Santos but without a ceasefire on the ground.
The talks, taking place in the Cuban capital Havana, are aimed at ending Latin America's longest-running insurgency that, over the course of five decades, has displaced some 4.5 million people and killed several hundred thousand.
One of the items on the agenda at the negotiations is the issue of the illegal cultivation of crops like coca.
Last month, the rebels called for the regulated cultivation and sale of the coca leaf, which is used to produce cocaine, opium poppies and marijuana as a fresh round of talks got under way.
Colombia, along with Peru, is the world's largest producer of cocaine, accounting for some 309 tons in 2012, according to the United Nations.