The Syrian army has strengthened its positions along the northeastern border with Lebanon to prevent weapons being smuggled in and fighters from entering.
Syria's opposition groups have made use of this largely porous territory. Many of those fleeing or wounded in the violence have been brought to Lebanon through the border.
Some Lebanese border villages, such as Mashariaa al-Qaa, have been dragged into the Syrian conflict.
Since the uprising began, Syrian security forces have slipped into the town in pursuit of what they call "armed terrorist groups".
The Lebanese government has made numerous complaints to the Syrian authorities but the incursions have not stopped.
Al Jazeera's Zeina Khodr reports from north-eastern Lebanon.