Syria air defences targeted Israeli missiles south of the capital Damascus on Monday, state news agency SANA said.

"The Israeli enemy is targeting the southern region with... missiles and our air defences are confronting them," a military source told SANA.

The Syrian Observatory for Human Rights, a Britain-based war monitor, said the missiles targeted positions of pro-government Lebanese Shiite group Hezbollah and allied Syrian fighters southwest of Damascus and in the southern province of Daraa.

There was no immediate report of a death toll.

Israel has carried out hundreds of raids in Syria since the civil war broke out in 2011, against Tehran-aligned Hezbollah and Iranian forces supporting Syrian President Bashar al-Assad, as well as government forces.

The Israeli army rarely acknowledges the strikes, but said that on August 3 it had used fighter jets, attack helicopters and other warplanes to hit Syrian military targets in southern Syria.

Hezbollah's leader Hassan Nasrallah on Sunday warned the group would kill an Israeli soldier for each of its fighters slain by the Jewish state, after one of its combatants was killed in an Israeli strike in Syria on July 20.

Syria's war has killed more than 380,000 people and displaced millions from their homes since it started in 2011 with the repression of anti-government protests.