A suicide bomber drove an apparently explosives-laden vehicle into two vans carrying Hezbollah operatives in eastern Lebanon early Tuesday morning, causing a number of casualties, Lebanon's Daily Star quoted security sources as saying. A 4X4 vehicle exploded in the Baalbek region, in the Bekaa Valley, some 2 kilometers from a "Hezbollah center," according to Lebanon's National News Agency.The area was cordoned off and multiple ambulances were seen entering the area to deal with the casualties.It was not immediately clear who was responsible for the incident.The sources said Hezbollah officials, alerted to a suspicious car soon after 3 a.m. (0100 GMT), began to follow it in two vehicles. The car then exploded.Footage broadcast by Hezbollah's Al Manar television showed at least two damaged vehicles, one of them overturned, and several piles of blackened, twisted metal scattered over a muddy and partially snow-covered plain.Al Manar's correspondent said the suspect car had been carrying about 50 kg (110 pounds) of explosives and its intended target was a Hezbollah base. He said there had been casualties and that villagers in the area also reported hearing gunfire.The incident occurred about 20 km (13 miles) from the border with Syria, whose 33-month-old conflict has fueled sectarian violence in Lebanon, including a series of car bombings which have killed scores of Sunni and Shi'ite Muslims.Many Lebanese Sunni Muslims support the rebels fighting to overthrow Syrian President Bashar al-Assad, whose Alawite faith is an offshoot of Shi'ite Islam. Shi'ite Hezbollah has sent thousands of fighters to support Assad, while many Sunni jihadis have flocked to Syria to join the rebels.The conflict has seeped back into Lebanon. Twin blasts struck the embassy of Iran - Hezbollah's patron - in Beirut last month. Bombs have also targeted Shi'ite districts of the capital and Sunni mosques in the northern city of Tripoli.On Tuesday evening, four missiles from Syria landed near the Shi'ite town of Hermel in the northern Bekaa, wounding two Lebanese army soldiers, a security source said. Sunni Syrian rebels have fired into the town several times this year. Hezbollah has been increasingly subject to attacks in Lebanon as its involvement in Syria's conflict on the side of President Bashar Assad has caused tensions with Sunni groups.In August, a car bomb killed 20 people in the southern suburbs of Beirut, a stronghold of the Shi’ite terrorist group.