The Israeli military says it has shot down an unmanned aircraft several kilometres off the coast of the northern port city of Haifa after it entered Israeli airspace from Lebanon.
"An unmanned aircraft (UAV) was identified approaching the coast of Israel and was successfully intercepted by IAF aircraft five nautical miles off the coast of Haifa at approximately 14:00 (1300 GMT) today," it said.
"I view with great gravity this attempt to violate our border," Israeli Prime Minister Binyamin Netanyahu said in a statement on Thursday.
"We will continue to do what is necessary to defend the security of Israel's citizens."
Last October, an Israel missile shot down a UAV, believed to have been sent by the Lebanese group Hezbollah, after it flew some 55km into southern Israel.
Israel waged a month-long war on Lebanon in 2006 after a Hezbollah cross-border raid. Since that incident, Israeli aircraft has regularly performed overflights into Lebanese territory.