Five Iran-backed fighters were killed on Sunday in a strike in Syria’s east, near the Iraqi border, a war monitor said, adding it was not clear yet who was behind the attack. “Five pro-Iranian fighters were killed and others were injured, some severely… after an unknown drone targeted the military vehicle they were in… near the Syrian-Iraqi border,” said the Syrian Observatory for Human Rights. The strike occurred in Syria’s eastern Deir Az-Zour province, where Iran wields significant influence and which is regularly targeted by Israel and the United States, according to the Britain-based moni…