Israeli air strikes killed 23 Syrian and foreign fighters in Syria Thursday, a monitor said, the latest in a spate of raids Israel has said targeted an Iranian presence on its doorstep.

Israel has pledged to prevent its main enemy from entrenching itself militarily in Syria, where it is backing President Bashar al-Assad's government alongside Russia and Lebanese militant group Hezbollah.

The pre-dawn raids killed three Iranians and seven Tehran-backed foreign fighters near Kisweh south of the capital, the Syrian Observatory for Human Rights said.

Eight Syrian air defence forces also lost their lives in both Mezzeh and Jisr Baghdad, west of the capital, the Britain-based war monitor said.

Five Syrian members of pro-Iran group were killed in the Ezra area in the southern province of Daraa.

A Syrian army source quoted by state news agency SANA said air defences responded to two waves of Israeli strikes after midnight that targeted the Damascus area and then positions in Daraa and the adjacent province of Quneitra.

"The attack wounded eight fighters," the source said, without elaborating on where they had been stationed or their nationality.

He said the raids were carried out from the airspace above the Israeli-occupied Golan Heights and southern Lebanon.