Lebanese state media say a suicide bomber has killed three people at a checkpoint manned by Hezbollah fighters near the Syrian border.
The National News Agency reports the bomber detonated his explosive-packed vehicle on Saturday.
No one has yet claimed responsibility for the bombing.
It was not immediately clear is the victims were Hezbollah fighters or bystanders.
Tensions are high at Lebanon's border with Syria, where groups are fighting to overthrow Syrian President Bashar al-Assad. Iran-backed Hezbollah supports Assad.
Some information for this report comes from AP, AFP and Reuters.