Suspicion fell on militant group Lebanese Islamic Hizbollah after an unmanned surveillance drone that flew into southern Israel was shot down by Israeli jets.
The drone crossed into the country's airspace from the Mediterranean, crossing the Palestinian territory of Gaza before being intercepted.
Although initial reports from a Palestinian news agency said the drone had come from Gaza, Israel denied this, adding that its aircraft had encountered it over Israeli territorial waters.
The source of the drone is a mystery but there have been two instances of Hizbollah-owned drones entering Israeli airspace in the past.
It is known that, in this incident, the drone was in flight over Israel for less than 30 minutes and was not carrying any explosives.