A convoy carrying members of the Lebanese Shi'ite militant group Hezbollah was hit by a roadside bomb near the Syrian border on Tuesday that killed one official and wounded two, security sources said.
The victims were Hezbollah security officials travelling in a convoy of two vehicles heading towards Syria. A barrage of gunfire hit the convoy after the blast, security sources said.
It was not immediately clear who was behind the attack, the third on the group since May. Syrian Sunni rebels have threatened to strike Hezbollah, one of Lebanon's most powerful political and military forces, in Lebanon following its military intervention in Syria on the side of President Bashar al-Assad.
Pictures from the scene showed black smoke rising from the cars. The windscreen of one of the vehicles had several bullet holes.
A truck driver who witnessed the attack said he had heard a blast, after which the Hezbollah GMC sport utility vehicle slowed to a halt.
Three or four gunmen arrived in another car and started firing at the vehicle. "Then they got back in their car and fled," the driver said.
Several small roadside bombs have been set off near the Syrian border crossing in recent months.
Last week a car bomb injured more than 50 people in a southern Beirut suburb controlled by Hezbollah. In late May, rockets were fired at a Hezbollah area of southern Beirut.
Lebanon, whose own 15-year civil war ended in 1990, is struggling to stay on the sidelines of its larger neighbour's conflict. Car bombs and clashes between groups supporting opposite sides of Syria's war have become increasingly common.