Iran's Revolutionary Guard has carried out 700 drone strikes against the Islamic State group in Syria, its aerospace chief told conservative Fars News Agency on Tuesday.

"Our bomber drones have carried out 700 military operations using smart bombs against IS," said Brig. Gen. Amirali Hajizadeh.

"They were used in eliminating tanks, personnel carriers, cars used for suicide attacks and 23-millimeter cannons – these were targets prized by IS and we significantly turned the tide of battle," he added.

The guard most recently used military drones against IS targets in Syria earlier this month, in retaliation for a deadly attack in September on a military parade in Iran's southwest claimed by the militant group.

Seven military drones as well as six ballistic missiles struck the "Islamic State headquarters" in the eastern Syrian town of Hajin, about 24 kilometers north of Albukamal bordering Iraq, state TV reported.

Iranian media said published images indicated the drones were locally-produced "Saegheh" craft, reverse-engineered from a US RQ-170 Sentinel captured by Iran in 2011.

Iran's armed forces chief of staff, Maj. Gen. Mohammad Bagheri, said at the time that the strikes were the first time the drones had "crossed multiple countries and reached their targets".

It was also the first time Iran had officially announced it was using combat drones outside of its borders, the conservative Tasnim news agency said.

Iran is a key backer of Syria's President Bashar al-Assad and a large contingent of Revolutionary Guard operate in the country as "military advisers."

The Syrian conflict began when the Baath regime, in power since 1963 and led by President Bashar al-Assad, responded with military force to peaceful protests demanding democratic reforms during the Arab Spring wave of uprisings, triggering an armed rebellion fuelled by mass defections from the Syrian army.

Hundreds of thousands of civilians have been killed in the war, mostly by the regime and its powerful allies, and millions have been displaced both inside and outside of Syria.

The brutal tactics pursued mainly by the regime, which have included the use of chemical weapons, sieges, mass executions and torture against civilians have led to war crimes investigations.