Lebanese officials say Syrian troops entered Lebanon and shot dead a Syrian farmer living in a border area.
Government and security officials in Beirut said the incident happened in a remote part of the eastern Bekaa Valley when Syrian troops entered Lebanese territory and opened fire, killing the farmer.
They said he was a Syrian married to a Lebanese woman.
There was no immediate explanation as to why he was targeted.
The BBC reports that the border between Lebanon and Syria in eastern Bekaa is "porous" and ill-defined.
It follows an incursion earlier in the week into neighbouring Lebanese territory by Syrian tanks.
The incidents have reinforced fears that Syria's problems may spill further into Lebanon.