An Israeli helicopter strike in Syria has killed six Hezbollah fighters, including the son of group's late military leader, sources close to the organisation have said.

Israel has yet to make an official statement on the attack, but local media has quoted a military source as saying the attack had targeted 'terrorists who intended to attack Israel'.

The missile strike hit a Hezbollah convoy in in the Syrian province of Quneitra, near the Israeli-occupied Golan Heights, reportedly killing Jihad Mughniyeh, the son of late Hezbollah commander Imad Mughniyah.

Struck: The helicopter strike killed six Hezbollah fighters, including Jihad Mughniyeh, pictured in 2008, the son of Hezbollah commander Imad Moughniyah

Five others were killed in the attack, including Mohammed Issa, a senior commander responsible for Hezbollah operations in Syria and Iraq, sources say.

The strike comes three days after Hezbollah leader Sayyed Hassan Nasrallah said he considered frequent Israeli strikes in Syria as a major aggression, and that Syria and its allies had the right to respond.

Hezbollah has been fighting alongside President Bashar al-Assad's forces in Syria's nearly four-year-old civil war.

The Hezbollah-run al-Manar news channel did not mention Moughniyah but said Hezbollah had confirmed that a group of its fighters were killed when they were checking an area in Quneitra.

It said Hezbollah would announce the names of the dead later on Sunday.

Guard: Israeli troops patrol the Israeli-occupied sector of the Golan Heights on Sunday

Attack: Lebanese media reported that an Israeli helicopter had fired two missiles on Quneitra

Like father, like son: Imad Moughniyah,was on the United States' most wanted list for attacks on Israeli and Western targets, before he was killed by a bomb in Damascus in 2008

Israel, Syria and the Golan Heights, locating the Israeli air strike Sunday

Quneitra has seen heavy fighting between forces loyal to Assad and rebels including fighters linked to al Qaeda.

'An Israeli helicopter fired two missiles on Amal Farms in Quneitra,' the Lebanese news channel said earlier, adding that two reconnaissance planes had also been seen flying over the area.

Israel has struck Syria several times since the start of the war, mostly destroying weaponry such as missiles that Israeli officials said were destined for Hezbollah, Israel's long-time foe in neighbouring Lebanon.

Syria said last month that Israeli jets had bombed areas near Damascus international airport and in the town of Dimas, near the border with Lebanon.