One person was killed in a roadside bomb blast that targeted a Syria-bound Hezbollah convoy in eastern Lebanon on Wednesday, a day after the attack.
The victim was travelling on board the convoy at the time of Tuesday's explosion, said the source, who was unable to confirm whether the dead man was a member of the powerful Lebanese Shiite movement.
The bomb struck one vehicle near the Masnaa border crossing.
Tuesday's bombing is the fourth time that a vehicle has been targeted by an explosive device in the Bekaa region, which is a Hezbollah stronghold.
Three previous bomb attacks targeted Hezbollah convoys, the security source said, adding that one of the blasts had wounded two Lebanese soldiers.
Hezbollah has dispatched fighters to battle alongside the Syrian regime against rebels seeking the overthrow of President Bashar al-Assad.
The conflict, pitting a Sunni-dominated rebel movement against Assad, whose Alawite faith is an offshoot of Shiite Islam, has raised sectarian tensions in Lebanon.