The Syrian army said early on Wednesday that Israel launched air strikes on an area in the southern outskirts of Damascus, where Syrian defectors say there is a strong Iranian military presence.
The air strikes are the second such attack within a week.
The latest strike killed at least eight fighters operating in pro-Iran militias, a war monitor said.
The nationalities of the dead fighters was not immediately known, the Syrian Observatory for Human Rights said.
The strike, which hit a strategically important area that Israel has struck before, originated in the disputed Golan Heights along the Israeli-Syrian border.
The aerial bombing caused only material damage, the Syrian army said.
Syrian military defectors said one air strike hit a military base in Jabal Mane Heights near the town of Kiswa, a rugged area 15 kilometres south of Damascus, where Iran's Islamic Revolutionary Guards Corps has long been entrenched.
Strikes in July also hit towns near Kiswa, where Hezbollah are posted with other pro-Tehran militias, a senior army defector said.
The area is defended by anti-aircraft missiles along the Syrian Golan Heights, the sources said.
"We don't comment on these kind of news reports," an Israeli military spokesman said.
Syrian state TV later broadcast footage of what it claimed was the most recent aerial attack.
For the past two years, Israeli air strikes have hit an area that extends from the southern countryside of Damascus to the Israeli-occupied Golan Heights, where a growing Iranian presence is regarded as a strategic threat by Israel.
Israel launched air raids against Syrian and Iranian targets in Syria last Wednesday, saying it would not tolerate Iranian military presence near its borders.
In Syria, President Bashar Al Assad's government has never publicly acknowledged that there are Iranian forces operating on his behalf, saying Tehran has only military advisers on the ground.
Analysts spoken to by The National, including the Long War Journal's Joe Truzman, say Israel's escalating air campaign in Syria is part of a deterrence strategy to slowly undermine Iran's military presence, without sparking a major increase in hostilities.
Defence officials have said in recent months that Israel would increase its campaign against Iran in Syria, where Tehran has expanded its presence with the help of its proxy militias.