Dozens of pro-Iran fighters killed in unidentified Syria strike
Two leaders were among those targeted in the assault that struck a convoy near the Syrian side of the Syrian-Iraqi border, near the city of Albukamal in the Deir az-Zour governorate, local sources told Anadolu.
A number of military vehicles were destroyed in the attack.
Iranian-sponsored militias in Deir al-Zour province have been regularly targeted by the US-led anti-IS coalition and Israel.
Iran is one of the Assad regime's key backers and thousands of militiamen from Iran-backed groups are present in Syria.
The most prominent Iranian militias are the Iranian Revolutionary Guards Corps (IRGC) and the Quds Brigade.
Most recently, warplanes suspected to be from the US-led anti-Islamic State (IS) coalition targeted positions belonging to pro-Iranian militias in eastern Syria on Friday.
A week earlier, a suspected Israeli strike killed nine fighters from Iran-backed militias near Syria’s border with Iraq. The Britain-based Syrian Observatory for Human Rights said Israel was "likely responsible" for the strikes near the Iraqi border.
Israel has launched hundreds of strikes in Syria since the start of the civil war in 2011.
It has targeted government troops, allied Iranian forces and fighters from the Lebanese Shia militant group Hezbollah.
It rarely confirms details of its operations in Syria, but says Iran's presence in support of President Bashar al-Assad is a threat and that it will continue its strikes.
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The uptick in attacks has prompted concern among Iran-backed forces in east Syria that Israeli agents may be among their ranks, the monitor said.
These forces have arrested four people on suspicion of providing intelligence to Israel, the war monitor reported last month.
The war in Syria has killed more than 380,000 people and displaced more than half of the country's pre-war population since 2011.