Two guerrillas belonging to the Revolutionary Armed Forces of Colombia were killed in combat with security forces just four days after a new peace deal was signed to end a half century of fighting.

The army in a statement said that they launched a manhunt for what it thought were members of the smaller National Liberation Army who had reportedly been extorting local ranchers and businesses in a lawless area of northern Bolivar state.

But a third gunman captured said he and his fellow gunmen belonged to the FARC's 37th front.

The rebels have yet to comment. But the government is trying to preemptively stem any fallout saying the rebels were 68 kilometers (42 miles) from where they are gathering to turn over their weapons to United Nations-sponsored peace monitors.