The attack happened in the Wadi Khaled region, where Syrian civilians and armed rebels have fled to escape violence in their own country, the BBC reported.
The first artillery shells from Syria Saturday morning landed on farm buildings and killed a woman, local residents said. During a second strike about an hour later, two more people died.
Several children are believed to be among the injured, residents said.
It was not immediately clear whether the victims were Syrian refugees or Lebanese nationals, the BBC said.
Wisconsin business offering 'therapeutic cuddling' forced to close
Exploding whale video goes viral on Internet