A 15-year-old boy was killed in the Golan Heights Sunday morning possibly by a mortar shell fired from Syria just south of the Quneitra crossing. Three others were hurt, including his father, a civilian contractor, who sustained serious injuries.

The attack had apparently targeted contractors working on the fence that Israel is building across the plateau.

The IDF responded with tank fire at areas under the control of forces loyal to Syrian President Bashar Assad.

A senior IDF official said Sunday that the army believes that fire on the Golan Heights on Sunday was a deliberate attack on Israel.

“A hole was found in the fence, following firing at a car that was conducting routine work,” the official said.

“The area is controlled by rebels, but it is not clear whether they were responsible for the shooting. Our initial response is artillery fire.

“The arena is isolated, we will investigate intelligence in the next couple of hours to understand who stands behind (the attack). The shooting towards the vehicle was most likely deliberate.

Three weeks ago, IDF forces fired artillery shells at a target in Syria after a mortar shell fired from the war-torn country hit Mount Hermon.

The Israel-Syria border region has seen intermittent exchanges of fire throughout the war in Syria. Although Israel has largely attributed these incidents to stray fire from clashes in Syria, there have been attempts to target Israeli soldiers.

In March, four IDF soldiers were injured by a roadside bomb outside the Druze town of Majdal Shams after the soldiers apparently spotted a suspicious person near the border fence and approached to investigate. The IDF suspected that attack was perpetrated by Lebanese terror group Hezbollah, which gained a foothold on the Syrian side of the Golan after it came to Assad’s aid in his fight against opposition forces seeking his ouster.

In response to that attack, the Israel Air Force targeted a Syrian army training facility, military headquarters and artillery batteries which the IDF said “aided and abetted” the roadside bombing attack. In confirming the response, Defense Minister Moshe Ya’alon said that Israel “won’t tolerate any breach of our sovereignty or any attacks against our soldiers and civilians… We will react with might and resolve against anyone who acts against us, no matter where and when, as we demonstrated last night.”

Hezbollah and regime forces managed to dislodge rebels from many of their positions along the Syrian border with Lebanon, but the sides continue to battle for positions along the border with Israel.