Two people were killed and four others injured when FARC guerrillas set off a bomb in the oil-rich eastern province of Arauca, the Colombian army said Monday.
The attack was carried out Sunday night by the 10th Front of the Revolutionary Armed Forces of Colombia, or FARC, the army's 18th Brigade said in a statement.
Rebels detonated "an explosive device of great power about 50 meters (164 feet) from a bridge" leading into the hamlet of Puerto Jordan, the military said.
Killed in the blast were a man and his 3-year-old son, while two other adults and two minors were hurt.
The injured received first aid at a clinic in Puerto Jordan before being airlifted by the army to a hospital in Arauca city.
The deadly bombing came just days before representatives of the Colombian government and the FARC are due to meet in the Norwegian capital for the formal inauguration of a peace process.
FARC units in the eastern province of Norte de Santander dynamited two electricity pylons on Sunday and announced an armed occupation of the area's key roads.
Both the security forces and the FARC say they plan to continue military operations alongside the peace talks.
The FARC has fought a succession of Colombian governments since the mid-1960s. EFE