JERUSALEM (AFP) - Israel carried out retaliatory air raids on Syrian army positions in the Golan Heights overnight, after a teenager on the Israeli side was killed in an attack from Syria, the army said early Monday.

"The IDF (Israeli army) targeted nine Syrian army positions in response to the earlier attack that originated in Syria killing an Israeli teenager and injuring two other Israeli civilians," an army spokesman said.

The targeted sites include Syrian military headquarters and launching positions, and "direct hits were confirmed", the statement added.

"Yesterday's attack was an unprovoked act of aggression against Israel... The IDF will not tolerate any attempt to breach Israel's sovereignty and will act in order to safeguard the civilians of the State of Israel," the spokesman Peter Lerner concluded.

The air raids came after the son of an Israeli defence ministry contractor was killed on the Golan on Sunday, in the most serious incident on the plateau since the Syrian war erupted in 2011.

Israel's defence ministry and the army said the boy, 13, died when a blast hit the car he was travelling in with his father and another contractor, both of whom were wounded.

The Israeli army called the explosion "an intentional attack" on a civilian vehicle by forces inside Syria, with a senior spokesman telling reporters Israeli tanks had fired at Syrian army posts in response.

It was not clear whether there were any casualties on the Syrian side.

Israel, which is still technically at war with Syria, seized 1,200 square kilometres of the Golan Heights during the 1967 Six-Day War and later annexed it in a move never recognised by the international community.

Since the Syrian conflict erupted in 2011, the plateau has been tense, with a growing number of projectiles, mostly stray, hitting the Israeli side and prompting occasional armed responses.

Over the past year, Israel has reportedly carried out a series of raids on Syrian and Hezbollah targets, but has not officially acknowledged doing so.