Israel forces shoot down a drone

Jerusalem (CNN) -- The Israeli air force shot down a drone approaching the nation's coast Thursday, the Israel Defense Forces said.

An Israeli F-16 shot the drone with air-to-air missiles, an Israeli military official told CNN. It went down five nautical miles off the coast of Haifa, and Israeli naval forces were searching the area while an investigation was initiated, the Israeli military said.

"I view with utmost gravity this attempt to violate our border," Prime Minister Benjamin Netanyahu said in a prepared statement. "We will continue to do everything necessary to safeguard the security of Israel's citizens."

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Thursday's incident marked the second time an unmanned aircraft had been intercepted in Israeli airspace within the past seven months, the IDF said.

In October 2012, Israeli warplanes tracked and eventually shot down a drone over the country's northern Negev Desert.

That drone did not carry any weapons or explosives, Israeli officials said at the time. They declined to discuss the drone's route or whether it had approached any sensitive facilities.

Hezbollah claimed responsibility for sending the drone, which Israeli officials at the time said appeared to have originated in Lebanon.

Hezbollah frequently flies drones over Israel, but the military rarely bothers to shoot them down, Michah Zenko of the Council on Foreign Relations said at the time.

CNN's Sara Sidner contributed to this report.