Two soldiers and one civilian died and another four civilians were injured in the east Colombian department of Arauca Tuesday, when rebels attacked an army checkpoint.
The attack took place in Fortul, a village less than 20 miles from the Venezuelan border.
According to local media, guerrilla fighters opened fire at the soldiers as a number of civilians were passing the checkpoint.
Authorities are investigating if the attack was carried out by the FARC or ELN, two leftist rebel groups with a strong presence in the Venezuelan border region.