Security officials say Lebanese forces have fired on Syrian aircraft that violated the country's airspace.
It was the first time since the outbreak of the Syria's conflict three years ago that the Lebanese military took action to prevent Syrian warplanes from violating its airspace.
Syrian forces have fired toward Lebanon in the past, trying to deter rebels from fleeing to the neighboring country or from sheltering in Lebanese border towns.
The Lebanese officials say the military opened anti-aircraft fire at two Syrian warplanes on Monday after the aircraft bombed a border area close to the eastern Lebanese town of Arsal.
The officials spoke on condition of anonymity because they weren't authorized to speak to the media.
There was no immediate comment from the Lebanese military or from the Syrian government.
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