Two soldiers were killed on Sunday in an attack by guerrillas of the National Liberation Army (ELN), according to the Colombian army.
The soldiers, who were on a motorcycle patrol in Arauca, in eastern Colombia on the border of Venezuela, were gunned down by “terrorists of the ELN” travelling in a vehicle, the army said in a statement.
Reinforcements were rushed to the area to search for the culprits, the statement added.
The ELN is Colombia’s second-largest rebel group after the Revolutionary Armed Forces of Colombia (FARC).
President Juan Manuel Santos and the FARC signed a peace accord on November 24 to end five decades of warfare, after the first agreement was unexpectedly rejected by Colombians in an October 2 referendum.
The ELN and the government began secret talks in January, 2014 to pave the way for official peace talks, but the process has stumbled over the issue of hostages and prisoners.
The Colombian government has suspended the preparatory talks until January 10, insisting that the ELN first release hostage ex-congressman Odin Sanchez.
The ELN in turn called for the simultaneous release of two imprisoned rebels.
More than 260,000 people have died in Colombia’s decades-long conflict, which drew in other guerrilla forces, right-wing paramilitary groups, drug traffickers and government troops.