The official SANA news agency and the state broadcaster both reported that air defences opened fire on "enemy targets" to "confront" them, without giving further details.

SANA said "a number of enemy targets were downed" by the air defences.

"It's an Israeli raid," said Rami Abdel Rahman, who heads the Britain-based Syrian Observatory for Human Rights war monitor.

"Missiles fired from Israeli planes targeted... arms depots southwest and south of Damascus that belong to Hezbollah or Iranian forces," he added.

Israel has carried out dozens of air strikes in neighbouring Syria against what it says are Iranian targets, many of them in the area south of Damascus.

At the end of November Syria said its air defences had targeted and downed a number of "hostile targets" over the Kisweh area south of Damascus.

An Israeli military spokeswoman declined to comment on reports of a strike in Syria when contacted by AFP.

But the military added in a statement: "An aerial defence system went off against an anti-aircraft missile launched from Syria. No damage or injuries were reported."

Experts say Israel is to be greatly affected by US President Donald Trump's announcement of a withdrawal of American forces from Syria, as it would leave the area open to Iran and its partners to develop their military capacity in the neighbouring country.

Israel, which had praised Trump's policies in the Middle East, has vowed not to let Tehran get a foothold in Syria.