Arauca deputy police commander Colonel William Arcos Perez confirmed that four people travelling in a vehicle in the rural area of Saravena were stopped and assassinated.
The guerrilla group allegedly killed two more people in the region on the same day, according to the colonel.
Perez added that the assassinations could be due to rivalries between drug factions within the ELN.
The ELN have reportedly been active in recent days. The group are accused of kidnapping the brother of a mayor and the mother of a town councilor in Arauca on Thursday and Friday, respectively.