A 15-year-old Israeli boy was killed in the Golan Heights Sunday morning in what the IDF said was a missile attack from Syria, just south of the Quneitra crossing. Three others were hurt, including his father, a civilian contractor, who sustained serious injuries.

A vehicle that was delivering water to the contractors, who were working on the fence that Israel is building across the plateau, was targeted with an anti-tank missile fired from the Syrian side of the border, military officials said.

The IDF responded with tank fire at “Syrian military posts in the immediate vicinity,” IDF spokesman Lt. Col. Peter Lerner said. The IDF was weighing a further response to what was regarded as a deliberate attack, military sources said later Sunday.

“This is not a case of errant fire but of an intended attack,” he said. “The IDF will continue to watch the northern border and react to developments in the field accordingly.”

Military sources said the army, after an initial investigation, concluded that the car had been targeted by an anti-tank missile.

The boy, Mohammed Karkara, from the town of Arraba in the lower Galilee, had accompanied his father to work on what was the first day of the summer vacation.

The boy’s father Fahmi told Army Radio there had not been any spillover from the civil war in that area previously. “We had heard the fighting, but quite far away.”

He said he had not been warned that it was dangerous to take his son with him to work in the area. After the explosion he said he knew “right away” that Mohammed was dead.

An Israeli army tank is seen stationed near the village of Majdal Shams, on March 19, 2014, in the Golan Heights. (photo credit: AFP/Jalaa Marey)

An Israeli army tank is seen stationed near the village of Majdal Shams, on March 19, 2014, in the Golan Heights. (photo credit: AFP/Jalaa Marey)

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.

Some Israeli experts said the area from which the anti-tank rocket was fired is under the control of Syrian rebels, not the Assad regime.

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.

AFP contributed to this report.