A 14-year-old boy was killed and three men injured at the Golan border on Sunday in the first fatal incident to involve Israeli citizens since the start of the Syrian civil war three years ago.

The boy was Muhammad Krakara, an Israeli Arab from the Galilee village of Arabeh. He had joined his father, the driver of a water-tanker being used in maintenance work on the border fence with Syria, on the first day of his summer holiday.

An advanced anti-tank missile hit the cab of the tanker and immediately killed Muhammad. His father and two other men were wounded.

IDF officers who examined the scene were initially uncertain whether it had been fired by forces loyal to the Assad regime or by one of the rebel groups active in the area.

On Tuesday, however, Foreign Minister Avigdor Lieberman accused the Syrian government of being behind the attack. "We got all the analysis, all the intelligence and it was clear it was Syrian authorities, [Bashar al-] Assad's forces, who fired on the Israeli boy," Mr Lieberman said.

"They must pay the price," he told Israel radio on Tuesday. "I hope Damascus got the message."

In retaliation, on Sunday night the IDF attacked nine Syrian army positions near the border with both air strikes and ground-launched, guided missiles.

There were conflicting accounts of the number of casualties resulting from the Israeli strikes. According to local Syrian activists, 10 people were killed, while the Syrian government claimed there were four fatalities.

Defence Minister Moshe Yaalon said that Israel would hold the Syrian government responsible for any attack on its territory. The Israeli government described the Golan attack as the most serious on the frontier since the start of the Syrian conflict.