At least four people were killed and seven wounded in overnight air raids by Syrian forces on mountains and valleys near the Lebanese town of Arsal, security sources said on Friday, the latest spillover of violence into the border area.

The five air raids struck close to Arsal, an area sympathetic to the mostly Sunni Muslim rebels fighting to topple Syrian President Bashar al-Assad, who is from Syria's Alawite minority.

Violence has regularly hit areas around Arsal. In January rocket fire from Syria killed at least seven people in the town and wounded 15.

Lebanon, which was pulled apart by its own civil war from 1975 to 1990, has been struggling to keep itself out of the three-year conflict in its much larger neighbour, which has stoked sectarian tensions across the region.

In Lebanon, groups have split along sectarian lines over the Syrian crisis and the country has faced increased car bombings in recent weeks, some hitting the capital Beirut. .