BEIRUT: An Israeli air strike in central Syria killed nine pro-government fighters, four of them Syrians and five of undetermined nationality, a Britain-based war monitor said Thursday.

The Syrian state news agency SANA had earlier quoted a military source as saying that the late Wednesday attack near the city of Palmyra had killed a soldier and wounded three others.

"At around 11:34 pm (2034 GMT) the Israeli enemy carried out an aerial aggression... on the area of Palmyra, targeting a communication tower and several positions in its vicinity," the source told SANA.

The Syrian Observatory for Human Rights, a Britain-based monitor, said the attack targeted several Iranian positions, among them the communication tower, near the T4 airbase east of Palmyra.

It reported that the attack killed four Syrians fighting with pro-Iran groups backing the Damascus government including one soldier, as well as five others whose nationality was not immediately clear.

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Last week, an Israeli missile strike on the same airbase killed two pro-Iran foreign fighters, the Observatory reported.

SANA said six soldiers were wounded in that attack.

Since the outbreak of the Syrian civil war in 2011, Israel has routinely carried out air strikes inside Syria, mostly targeting Syrian government troops as well as allied Iranian and Lebanese forces.

The Israeli army rarely acknowledges individual strikes but has said repeatedly that it will not allow Syria to become a stronghold of its arch-foe Iran.

Before the latest strike, Israel's head of military intelligence, Major General Aharon Haliva, said Iran was "continuing to promote subversion and terror" in the Middle East.

"We will continue to hinder Iran's actions, to hedge and harm its abilities, and take action to preserve Israel's power," he said in comments relayed by the military.