JERUSALEM –  Israel fired a Patriot missile at an unmanned aircraft that approached the country’s border from Syria for the second time this week, the military said Friday.

The defense system was fired at a Syrian drone “flying over the demilitarized zone,” adding that it was “most likely intercepted,” the military said.

It said the military will “operate against attempts to violate the 1974 Separation of Forces Agreement, threats to Israeli sovereignty and any attempt to harm Israeli civilians.”

Israeli leaders have recently reiterated that they expect Syrian President Bashar Assad and his Iranian-backed allies to honor the agreement which sets out a demilitarized zone along the frontier and limits the number of forces each side can deploy within 15 miles of the zone.

On Wednesday, a drone traveled about 6.2 miles inside Israeli territory before it was shot down. That incident came as Prime Minister Benjamin Netanyahu visited Moscow for talks with Vladimir Putin about Syria and Iran. Russia has been a key ally of the Syrian government in its civil war. Israel’s main concern is keeping archenemy Iran, an Assad ally, as far away from its border as possible — along with its proxy, the militia of Lebanon’s Hezbollah.

The Israeli military targeted Syrian military positions Thursday in response.

Last month, Israel fired a missile at a drone that approached its airspace near the Syrian frontier, and in February it shot down what it said was an Iranian drone that entered its airspace. It bombed Iranian targets in Syria in response.