The military airport of Mazze, in the west suburbs of Damascus, was hit by a "possible Israeli missile, which hit a munitions store setting off successive explosions," the head of the Syrian Observatory for Human Rights Rami Abdel Rahmane told AFP.

The airport houses Syrian Air Force intelligence, and in early 2017 the Syrian regime accused neighbouring Israel of bombing the base.

A Syrian military source said that "the Mazze airport was not the target of Israeli aggression," according to a Saturday report by the official Sana news agency.

"The explosions heard were due to an explosion at a munitions deposit close to the airport which was due to an electrical short circuit," the source said.

Israel has sought to avoid direct involvement in the conflict but acknowledges carrying out dozens of air strikes in Syria to stop what it says are deliveries of advanced weaponry to its Lebanese enemy Hezbollah.

It has also pledged to prevent its arch foe Iran from entrenching itself militarily in Syria, and a series of strikes that have killed Iranians in Syria have been attributed to Israel.

Earlier this week, Israel reiterated its threat to hit Iranian military targets in Syria.

"The IDF (Israel Defence Forces) will continue to take strong and determined action against Iran's attempts to station forces and advanced weapons systems in Syria," Prime Minister Benjamin Netanyahu said.

In July, Syria accused Israel of bombing a military post in the northern province of Aleppo, where the Observatory reported at least nine pro-regime fighters died.

More than seven years since the conflict began, regime forces have managed to retake entire regions from rebels and jihadists and now control nearly two-thirds of the country.

Syrian troops are supported military by their Russian and Iranian allies, as well as by Lebanese Hezbollah fighters and Iraqi, Iranian and Afghan militiamen.