Iran has condemned the Israeli offensive in Syria-controlled Golan Heights which resulted in the killing of several Hezbollah militants including some key figures.

Accusing Israel of spearheading "state-funded" extremist activities, the Iranian foreign ministry has censured the onslaught, which took place near the border with Israel.

"We condemn all actions of the Zionist regime [of Israel] as well as all acts of terror. The policy of state terrorism in a known policy of the Zionist regime [of Israel]," Iranian Foreign Minister Mohammad Javad Zarif told Press TV.

Israeli Defence Forces (IDF) is widely believed to be behind the attack but they have not officially commented on the operation as yet.

The Lebanese group Hezbollah, often seen as the long arm of Iran, has admitted at least six militants were killed after the Israeli helicopter fired missiles.

A statement from the extremist organisation read: "While a group of Hezbollah fighters were conducting a field inspection in the town of Mazraat el-Amal in the Syrian region of Quneitra, they were subjected to rocket fire from Israeli enemy helicopters, which led to the fall of several martyrs whose names will be announced at a later stage after informing their respective families."

Jihad Mughniyeh, the son of slain Hezbollah leader Imad Mughniyeh, is said to be among those killed. Local reports from Israel suggest that the strike was carried out after there were indications that the militant group was plotting a high-profile attack against Israeli interests.

Shortly after the attack, the Hezbollah-run Al-Manar TV warned that the latest Israeli offensive puts the "whole Middle East on edge."