Israel on Monday denied reports that a rocket was fired at its territory from southern Lebanon, dpa reported.
The Lebanese National News Agency said the rocket was fired from the area of Marjeyoun overnight and hit Metulla in nothern Israel.
That report cited an unnamed Lebanese security source who said there were no casualties.
An Israeli military spokeswoman said an explosion was heard, but there was no evidence of a projectile or impact.
"As of now nothing has been found," but Israeli troops were searching the area, she said.
The reported incident occurred one day after rockets landed in a Beirut stronghold of the Hezbollah Shiite movement, injuring at least five people.
Tensions throughout the region have been heightened over the Syrian conflicts, which has so far killed more than 80,000 people.
Damascus also vowed to respond to an Israeli airstrike this month that targeted convoys and depots in Syria that were shipping weapons to Hezbollah, Israeli officials said.