BOGOTA (AFP) ― At least 20 leftist rebels were killed in Colombia after the military launched bombing strikes against their camp in Narino province, near the border with Ecuador, the army announced late Sunday.

The rebels belonged to the Revolutionary Armed Forces of Colombia (FARC), the country’s largest guerrilla group, according to General Leonardo Barrero, a local military commander.

He said the guerrillas belonged to the mobile Marshal Sucre column who had set up a base in the area. At least three separate guerrilla camps were bombed during the operation at dawn Saturday.

The strike came as Colombian President Juan Manuel Santos warned FARC leaders Sunday that they had less than a year to reach a negotiated end to Latin America’s longest-running insurgency.

“This has to be a process of months, rather than years. In other words, this should not last any longer than November next year at the latest,” the president said at an event in the Caribbean resort city of Cartagena.

The FARC, Latin America’s longest insurgency, started talks formally with Bogota on Oct. 18 in neutral Norway. The talks moved to Havana on Nov. 19 and will resume this week.

It is a conflict that has dragged on for almost a half century, with some 600,000 dead, 15,000 missing and four million people domestically displaced.