Israel struck what it said were Iranian targets in Syria early on Monday in response to rocket fire it blamed on Iran, sparking concerns of an escalation after a monitor reported 11 fighters killed.

Israel openly claimed responsibility for the strikes against facilities it said belonged to the Iranian Revolutionary Guards’ Quds Force, continuing its recent practice of speaking more openly about such raids.

It said the strikes were in response to a surface-to-surface rocket the Quds Force fired from Syria at the Golan Heights on Sunday, which Israeli air defences intercepted.

“Iranian Quds forces operating in Syrian territory launched a surface-to-surface rocket from Syrian territory aimed at the northern Golan Heights,” the Israeli military said in a statement.

“In response to the attack, during the night [Israeli military] fighter jets struck Iranian Quds Forces military targets in Syria in addition to Syrian aerial defence batteries.”

It said targets included munitions stores, a site at Damascus International Airport, an Iranian intelligence installation and an Iranian military training camp.

It said it had also hit Syrian air defence batteries in response to fire from them.

The Syrian Observatory for Human Rights war monitor said at least 11 pro-regime fighters including two Syrians were killed.

Russia, which like Iran is a key backer of Syrian President Bashar al-Assad in the country’s war, said the Israeli strikes killed four Syrian soldiers and wounded six, while also damaging Damascus airport infrastructure.

Hezbollah ‘also targeted’

The Observatory said air strikes and ground-to-ground missiles hit several targets around the capital including near the Damascus airport, as well as near the Thaala military airport to the south of the capital.

The targets included weapons depots belonging to the Lebanese Shiite movement Hezbollah and Iranian fighters, it added.

Israel’s interception of the rocket on Sunday came after Damascus accused Israel of carrying out air raids in the country’s south.

As Israel announced its strikes on Monday, Syrian state news agency Sana said its country’s air-defence systems had responded to “enemy” fire.

Israel has pledged to stop its main enemy Iran from entrenching itself militarily in neighbouring Syria.

It has carried out hundreds of air strikes there against what it says are Iranian military targets and advanced arms deliveries to Tehran-backed Hezbollah.

Its fighter planes have faced anti-aircraft fire during such raids, but it has rarely faced surface-to-surface rocket fire in response.

On Sunday, Sana quoted a military source saying Syria’s air defences went into action after Israel earlier in the day launched air strikes on the south of the country.

In those strikes, the Russian army said Syrian air defences had destroyed seven Israeli projectiles, after four of the Jewish state’s F-16 military planes “fired rockets into Syrian territory”.

Israeli Prime Minister Benjamin Netanyahu told reporters on Sunday that “we have a permanent policy – to strike at the Iranian entrenchment in Syria and hurt whoever tries to hurt us”.

Netanyahu and other Israeli officials have been speaking more openly about the country’s strikes on Syria in recent days, which some analysts partly attribute to the premier wanting to burnish his security credentials ahead of April 9 elections.

But Israel also risks an escalation with Syria and Iran, as well as possibly further angering Russia.

Military coordination between Israel and Russia in Syria took a hit after a friendly fire incident in September that led to a Russian plane being downed by Syrian air defences during an Israeli raid.

The incident angered the Kremlin and complicated Israel’s operations in Syria, particularly as Moscow delivered an advanced air defence system there in response.

Israel has sought to maintain its coordination with Russia as well as its free hand to strike in Syria.

On Thursday, Israeli military officials concluded a series of talks with their Russian counterparts aimed at improving their coordination there.

More than 360,000 people have been killed and millions displaced since the start of Syria’s civil war with the brutal repression of anti-government protests in 2011.