Army units cordoned off the area and ended Friday's firefight, which lasted about an hour and a half, between the al-Jaafar and Zeiter Shia Muslim clans in the ancient town of Baalbek.
Three men were caught in the crossfire and wounded, one seriously. He was rushed to a hospital in Beirut.
Parliament member Ghazi Zeiter blamed the clashes on past killings and disputes between the two clans. Clashes between the two clans last year killed at least four people on both sides before reaching a Syrian-brokered settlement.
International pressure forced Syria to withdraw its troops from Lebanon in April after the assassination of former Lebanese prime minister Rafiq al-Hariri.
Parliamentary elections are taking place by region, phased over four weekends.