A convoy of lorries coming from <a href="https://www.thenationalnews.com/mena/iraq/" target="_blank">Iraq</a> was attacked by drones in eastern <a href="https://www.thenationalnews.com/mena/" target="_blank">Syria </a>on Sunday night, opposition activists and a pro-government radio station have said. "Seven truck drivers and their assistants, all of them non-Syrians, were killed as a result of unidentified aircraft targeting a convoy of Iran-backed groups last night," the Syrian Observatory for Human Rights said. The drones, believed to have been sent by the US-led coalition, struck six refrigerated lorries, the UK-based opposition war monitor said. The attack was in the Syrian border region of Al Bukamal, a known stronghold of Iran-backed militias, in Deir Ezzor province. No group has yet claimed responsibility. Omar Abu Layal, a European-based activist from Deir Ezzor who runs a group that monitors developments, said the drones struck an Iran-backed militia convoy. The attack comes at a time of heightened tension between <a href="https://www.thenationalnews.com/mena/iran/" target="_blank">Iran</a> and its rivals in the region. The pro-government Sham FM radio station also reported that six refrigerated lorries were hit. In Baghdad, an Iran-backed militia member confirmed there was a strike but said it only hit one lorry. He gave no word on casualties. The attack in eastern Syria came hours after bomb-laden drones struck an Iranian defence factory in the central city of Isfahan, causing some damage to the plant. Last month, Israel’s military chief of staff strongly suggested that Israel was behind a strike on a lorry convoy in Syria in November, giving a rare glimpse of the country's shadow war against Tehran and its proxies across the region. Lt Gen Aviv Kochavi, who retired this month, said Israeli military and intelligence capabilities made it possible to strike specific targets that pose a threat. Israeli leaders have, in the past, acknowledged striking hundreds of targets in Syria and elsewhere in what it says is a campaign to thwart Iranian attempts to smuggle weapons to militant proxies such as Lebanon’s Hezbollah or to destroy weapons caches. The November strike hit fuel tankers and other lorries carrying weapons destined for militias in Syria’s eastern province of Deir Ezzor, the Observatory reported at the time. It said at least 14 people, most of them Iran-backed militiamen, were killed in the strike along the border with Iraq. Two paramilitary officers in Iraq confirmed that some of those killed in the attack were Iranian. At the time, Israel declined to comment on the strike. Iran is a key backer of Syrian President Bashar Al Assad and has sent thousands of fighters to help his forces during the country’s 11-year civil war. Both Iran and the Assad administration are also allies of Hezbollah, which has fought alongside Syrian forces in the war. Israel considers Iran to be its chief enemy and has issued a warning against what it views as its hostile activities in the region.