Artillery fire from Syria killed two people and injured at least four others in northeastern Lebanon on Sunday, the Lebanese army and state news agency said.
"This afternoon, the border town of Qasr in the Hermel border region came under artillery shell fire from Syrian territory, killing one citizen, injuring three others and damaging several homes," the Lebanese army said in a statement.
"Subsequently, army units were deployed widely across the area and took measures in the field necessary to protect people and respond to the source of the attack as appropriate."
Shortly afterwards, Lebanon's state NNA news agency reported a second death in the village Hosh Sayyed Ali in the same region.
"A 13-year-old... died as a result of wounds from rocket fire from southern Syria on the village of Hosh Sayyed Ali on the border, which also injured one person," the agency said.
There was no indication that the Lebanese army was gearing to return fire in response to the latest spillover of the conflict in neighbouring Syria.
Lebanese President Michel Sleiman issued a statement after the incident in Qasr, condemning the fire and adding that such spillover "has only led to the deaths of innocent Lebanese who have nothing to do with the ongoing conflict taking place outside their country."
The deaths are not the first time that Lebanese citizens have been killed by cross-border fire coming from Syria. In February, at least one Lebanese man was killed by gunfire from the Syrian side of the border.
Since the Syrian uprising began in March 2011, there have been numerous deadly clashes along the northern and eastern borders of Lebanon, usually between the Syrian army and armed Syrian or Lebanese groups backing the uprising.
There have also been clashes between armed groups and the Lebanese army seeking to prevent the infiltration of fighters into Lebanon.
Beirut has officially adopted a neutral policy towards the Syria conflict, but it has deepened divisions in the country, with the Sunni-led March 14 movement supporting the revolt and the Shiite Hezbollah and its allies backing the regime.