Lebanon's Hezbollah on Saturday blamed Islamist extremists for killing the Shia militant group's top military commander in Syria in an artillery attack.

‘An investigation has shown that the blast that targeted one of our positions near the Damascus international airport that led to the martyrdom of the brother commander Mustafa Badreddine was caused by artillery bombardment carried out by takfiri groups present in that region,’ a Hezbollah statement said.

It did not name any particular group and there has been no claim of responsibility for the attack, which pro-Hezbollah media said happened on Thursday night.

The Iran-backed movement has deployed thousands of fighters in Syria where Badreddine led its intervention in support of President Bashar al-Assad.

Hezbollah has been battling opponents of the regime including extremists from the Islamic State jihadist group and Al-Nusra Front, Al-Qaeda's Syria affiliate.

In its statement Saturday, a day after thousands attended Badreddine's funeral in Beirut, Hezbollah vowed no let up in its war against those it describes as ‘criminal gangs’ in Syria.

‘The result of the investigation will only increase our determination and will to pursue the fight against those criminal gangs until they are defeated,’ the statement said.

‘It is the same battle against the American-Zionist scheme in the region, which the terrorists are spearheading,’ it added.

Badreddine was on a US terror sanctions blacklist, was a key suspect in the 2005 assassination in Beirut of Lebanese ex-premier Rafiq Hariri and was one of the ‘most wanted’ by Israel.

His predecessor, cousin and brother-in-law Imad Mughniyeh, was killed in Damascus in a 2008 bombing that Hezbollah blamed on its regional arch-foe Israel with whom it has fought several wars.