Three people were killed when gunfire from Syria hit their car in the Lebanese northern border area of Wadi Khaled, the state-run National News Agency (NNA) reported.
The gunfire came from the Syrian side of the border and hit a car on the Lebanese side, killing three passengers in the car, according to the report.
The dead men were all Lebanese, and their bodies were transported to a hospital in Wadi Khaled, Xinhua reported.
According to United Nations figures, nearly 5,000 Syrians fled to Lebanon since mid-March when protests in Syria escalated into armed clashes. The majority of those people reside in the northern area of Wadi Khaled and the north-eastern region of Arsal.
Syria accuses Lebanese groups, including the Future Movement of former Prime Minister Saad Hariri, of assisting armed gangs in Syria by providing money and weapons.
Last week, Lebanon's Defense Minister said the Lebanese Army had information that members of Al-Qaeda were penetrating Syria through Arsal.