ARSAL, Lebanon — This Lebanese border town has become a safe haven for war-weary Syrian rebels, a way station for wounded fighters and home to hundreds of frightened Syrian refugee families. Residents of Arsal, a Sunni Muslim town of 40,000, say they have strong motives to help those trying to topple Syria's regime: they themselves were harassed and abused by it during three decades of de facto Syrian control of Lebanon. But in siding with the rebels, many of them fellow Sunnis, Arsal is also deepening rifts with its Shiite neighbors in the Bekaa Valley that runs along Lebanon's eastern border with Syria. Large areas of the scenic valley are controlled by Hezbollah, the powerful Shiite militia that is supporting and — according to the US and the Syrian opposition — also fighting alongside Syrian President Bashar Assad's forces. For now, Lebanon's rival political and religious groups have largely tried to keep a lid on domestic tensions stoked by the conflict next door, with collective memories here still scarred by Lebanon's own 15-year civil war that ended in 1990. But any major escalation in Syria or miscalculation by the combatants' Lebanese supporters could ignite Lebanon's explosive sectarian mix. Unlike some parts of Lebanon, the Bekaa has not been hit so far by sectarian violence linked to the bloodshed in Syria, although a drive along the valley's bustling main thoroughfare and the string of towns that line it, shows where the region's Shiite and Sunni loyalties lie. In predominantly Shiite Baalbek, one of the Bekaa's larger towns, a downtown billboard shows Hezbollah leader Hassan Nasrallah next to Assad, who is decked out in a military uniform and aviator glasses. “They will not weaken our resolve,” reads a defiant caption. The presence of Iran, the region's Shiite power and a patron of both Hezbollah and Assad, is also visible: A poster of Iranian President Mahmoud Ahmadinejad, with the slogan, “We can,” hangs from roadside poles along a four-lane highway that signs boast was partially funded by Tehran. A turn off the highway and down a winding uphill road, leads east toward the Syrian border and Arsal. Homes here are bare-bones, made of raw gray cinderblock, without stone facades. A spray-painted Syrian rebel flag — with green, white and black horizontal stripes and three red stars on the white — decorates one of the walls in the center of town. Bassel Hojeiri, principal of the local middle school, said people in Arsal back the rebels as fellow Sunnis fighting a regime controlled by Alawites, but also because of deep-seated hatred of Syria's rulers. As a border town, Arsal suffered under a particularly oppressive Syrian military presence when Damascus held sway in Lebanon from 1976 to 2005. Syrian troops at checkpoints near Arsal would sometimes beat area residents, arrest them without reason, demand cash or even seize cars, said Hojeiri, 37, a former mayor of Arsal. “People hated them,” Hojeiri said of the Syrian occupiers. “Now hopefully their time is ending.” For years, religious differences seemed unimportant, Hojeiri said. Even during Lebanon's civil war, with its frequently shifting alliances, Shiites and Sunnis were partners more often than they were foes. However, Sarkis Naoum, a columnist for Lebanon's An Nahar daily said the sectarian tensions bubbling under the surface could erupt at any time. “If anything major happens, what is happening in Syria could expand into Lebanon,” he said. — AP