=DAMASCUS, Sept. 9 (Xinhua) -- At least 18 pro-government fighters were killed in eastern Syria by airstrikes after mid-night, a war monitor reported on Monday.
Unknown warplanes carried out airstrikes against Iranian-run military bases and weapon depots in the Al-Bukamal city and nearby areas in the eastern countryside of Deir al-Zour province in eastern Syria near the Iraqi border.
The Syrian Observatory for Human Rights said the slain fighters were Iranians and allied fighters, noting that the warplanes are yet to be identified.
The UK-based watchdog group said the death toll could likely rise due to the number of critically wounded fighters.
Meanwhile, the state-run media outlets in Syria are yet to comment on the reports emerging about the airstrikes in eastern Syria.
In June of 2018, Israeli airstrikes killed 55 Iranian and pro-Iranian fighters in near Al-Bukamal.
It's worth noting that Iranian military advisors and fighters of the Lebanese Hezbollah group have military posts in eastern Syria.
The Lebanese Hezbollah group announced shooting down an Israeli drone over southern Lebanon early Monday after it crossed the border towards the southern Lebanese town of Ramyah.
The incidents are the latest escalation between the Iranian-backed fighters and Israel as Hezbollah has recently destroyed Israeli drones over Lebanon.
Israel considers Iran its arch-foe and has carried out hundreds of deadly airstrikes in Syria, charging the attacks target Iranian sites and weapons convoys to Hezbollah.