The Israeli military was, on Monday, investigating a possible overnight attack launched from Lebanon on a northern border town, after residents reported hearing explosions.
"Residents in Metullah reported hearing booms. We are still checking the area and haven't found anything yet," a military spokeswoman told AFP.
There was no official confirmation from Beirut, but military and security sources in southern Lebanon reported hearing the "sound of a blast", without being able to provide details on its source.
The report comes less than a day after two rockets exploded in the Hizbullah heartland of Beirut's Shiite southern suburbs, wounding four Syrian workers.
That attack came hours after Hizbullah vowed to fight until victory for Syria's regime.
A Lebanese security source said the rockets had been fired from Aitat in the Mount Lebanon area, some 13 kilometres (eight miles) southeast of where they hit, AFP reported.