JERUSALEM – Israel scrambled fighter jets to intercept a drone Saturday that crossed deep into Israeli airspace from the Mediterranean Sea, shooting the aircraft down over the country's southern desert, the military said.

The incident marked the first time in at least six years that a hostile aircraft has penetrated Israel's airspace, and Israeli officials said they were taking the incident seriously, raising the possibility of retaliatory action.

It was not immediately clear who launched the drone, but suspicion quickly fell on the Lebanese Islamic militant group Hezbollah. The Iranian-backed group is known to have sent drones into Israeli airspace on several previous occasions.