A roadside bomb targeted on Monday a Hezbollah passenger van from Lebanon to Syria, reported LBCI television.
It said that the explosive was placed in an alley behind the Customs building in the Bekaa town of Chtaura.
The bomb went off, but no one was injured in the attack.
The army has since cordoned off the area, discovering a second bomb in the process.
It is currently dismantling it.
A security source later denied to Voice of Lebanon radio (100.5) the existence of a second bomb, adding that security forces did not halt the van that was targeted.
Ever since taking part in fighting alongside the Syrian regime against the country's uprising, Hezbollah has become a target of attacks by armed groups that support the rebels.
A number of bombings have struck Hezbollah strongholds in Beirut's southern suburbs and in the Bekaa region in recent years.

Al Bawaba