The Israeli military says it has carried out airstrikes on a number of military targets inside Syria, including the military headquarters, in response to a cross-border attack that left an Israeli teenager dead.

In a statement early Monday, the military said nine targets were struck and "direct hits were confirmed."

"Yesterday's attack was an unprovoked act of aggression against Israel, and a direct continuation to recent attacks that occurred in the area," said Lt. Col. Peter Lerner, a military spokesman. He said Israel "will not tolerate any attempt to breach Israel's sovereignty and will act in order to safeguard the civilians of the state of Israel."

In the initial deadly incident, a civilian vehicle in the Israeli-controlled Golan Heights was targeted, killing a 14-year-old boy in the first deadly incident along the volatile area since the Syrian civil war erupted more than three years ago. Israel first retaliated with tank fire at Syrian government targets.

The Israeli military said two other people were wounded in Sunday's incident.

Lt. Col. Peter Lerner, an Israeli military spokesman, said it was "the most substantial incident" along the frontier with Syria since the beginning of the civil war. He said it was unclear whether the vehicle had been struck by a rocket, mortar shell or some other explosive device, but claimed the attack was clearly intentional.

"It was fired directly from east to west," he said, adding that it was a "direct hit" on the vehicle.

The vehicle was driving along a fence that Israel has built along the Syrian frontier, Lerner said. He described the vehicle as a water tanker, and said people on board were doing work for Israel's Defense Ministry at the time. "We have a hole in the fence, which indicates it could be a projectile," Lerner said.

He said Israeli tanks opened fire in response at Syrian government positions, but that it remained unclear whether the Syrian military or rebels had carried out the attack. Israel has said it holds Damascus responsible for any attacks emanating from its territory.

Later Sunday, Prime Minister Benjamin Netanyahu said he spoke to the boy's father and sent his condolences. "Our enemies don't differentiate between Jews and non-Jews, adults and children," he told an international gathering of Jewish journalists.

Israel has not taken sides in the Syrian civil war. While closely watching the fighting, it has largely stayed out of the violence, though it has occasionally responded to fire that has landed on the Israeli side of the Golan.

In his address, Netanyahu said in conflicts like Syria, where al-Qaeda-inspired extremists are battling Iranian-backed Syrian troops, there is no good choice and it is best for Israel to sit back and let its enemies weaken each other. "This is a fault line between civilization and savagery," he said.