Sources told The (Beirut) Daily Star newspaper on condition of anonymity three rockets were fired by Syrian aircraft at the border town of Khirbet Daoud. There were no casualties reported.
Syria's grip over Beirut weakened after Lebanon's Cedar Revolution in 2005, but national security has again come under threat from Syria's civil war.
Security concerns were intensified when Hezbollah admitted to fighting alongside pro-government forces in Syria. A series of bomb attacks and acts of violence followed the revelation. The European Union listed Hezbollah's armed division as a terrorist entity last month.
Lawmakers in Lebanon are debating the arsenal of the Shiite movement, which holds political office in Beirut. Pro-Hezbollah leaders say its weapons are needed to deter Israel, though opponents say they're a threat to national security.
The attack on Khirbet Daoud is the third such incident this year. A resident of the border area was injured slightly in an April rocket attack. The area is considered a route for illegal weapons transfers across the border.