Missile fire is seen from Damascus, Syria May 10, 2018. Image Credit: REUTERS

Beirut: Iranian forces in Syria launched a rocket attack on Israeli army bases in the Golan Heights early on Thursday, Israel said, prompting one of the heaviest Israeli barrages in Syria since the conflict there began in 2011.

The attack on the Israeli-occupied Golan Heights, just past midnight, marked the first time Iranian forces have hit Israel from Syria, where they have deployed along with Iran-backed militias and Russian troops to support President Bashar Al Assad in the seven-year-old civil war.

Israel said the Iranian salvo of 20 Grad and Fajr rockets were shot down by its Iron Dome air defence system or fell short of the Golan targets. The Quds Force, an external arm of Iran's Revolutionary Guards, carried out the launch, Israel said.

"It was commanded and ordered by (Quds Force chief General) Qassem Soleimani and its has not achieved its purpose," military spokesman Lieutenant-Colonel Jonathan Conricus told reporters.

Israel retaliates

Israel struck back by destroying dozens of Iranian military sites in Syria, Conricus said, as well as Syrian anti-aircraft units that tried unsuccessfully to shoot down Israeli planes.

"We do not know yet the (Iranian) casualty count," he said.

"But I can say that in terms of our purpose, we focussed less on personnel and more on capabilities and hardware ... to inflict long-term damage on the Iranian military establishment in Syria. We assess it will take substantial time to replenish."

Syrian state media said dozens of Israeli missile strikes hit a radar station, Syrian air defence positions and an ammunition dump, underscoring the risks of a wider escalation involving Iran and its regional allies.

Syria war monitor says Israeli strikes killed 23

The Britain based Syrian Observatory for Human Rights said the overnight attacks struck several military posts for the Syrian troops and Iranian-backed militias near the capital, Damascus.

The head of the Observatory, Rami Abdurrahman, said five Syrian soldiers, including two officers, and 18 militia fighters were killed. Abdurrahman says it is not immediately clear if Iranians were among those killed.

He says the toll is likely to rise because some of the wounded are in critical condition.

The Observatory says the strikes targeted suspected locations of the Lebanese Hezbollah group, as well as areas where Iranian advisers are believed to be based.

Iran vowed retaliation after a suspected Israeli air strike last month killed seven of its military personnel in a Syrian air base. Israel regards Iran as its biggest threat, and has repeatedly targeted Iranian forces and allied militia in Syria.

France's Macron calls for de-escalation in Syria

French President Emmanuel Macron called for a de-escalation of tensions "The president has been kept regularly updated. He calls for a de-escalation in the situation," Macron's office said in a statement.

Macron will discuss the Middle East in a meeting with German Chancellor Angela Merkel later on Thursday, the Elysee said.

Moscow calls to dial down tensions

Also Russia vocalised its concern about the growing military tensions between Israel and Iran over Syria and called for them to de-escalate this morning.

Russia's Deputy Foreign Minister Mikhail Bogdanov said on Thursday, "This is all very alarming, it causes concern. There should be work to de-escalate the tensions,"  the TASS news agency reported.

Adding that  "28 Israeli F-15 and F-16 aircraft were used in the attack, which released around 60 air-to-ground missiles over various parts of Syria. Israel also fired more than 10 tactical ground-to-ground missiles,"

German Foreign ministry have accused Iran of "provocation" 

"These attacks are a serious provocation that we strongly condemn. As we have always emphasised, Israel has a right to self-defence," said a German foreign ministry spokeswoman in a statement. She added however that it is "crucial that there is no further escalation".

To that end, she said "a sustainable political solution" must be found to end the conflict in Syria, "so as to end the suffering of the Syrian people, but also so as not to further jeopardise stability in the whole region".