Seven people including several civilians were killed Wednesday when a drone strike targeted a weapons factory belonging to Iran-backed factions in government-held eastern Syria, a war monitor said. It was not immediately clear who was behind the strike in Deir Ezzor province, where Iran-backed factions hold sway and where a US-led coalition and Israel have previously carried out attacks. "Seven people were killed and 15 wounded in a drone strike targeting a weapons factory and a truck loaded with weapons," both belonging to Iran-backed groups, said Rami Abdel Rahman, who heads the Britain-based Syrian Observatory for Human Rights. Three pro-Iranian fighters from Afghanistan, three Syrian civilians and one unidentified Syrian were killed, Abdel Rahman told AFP, adding that the building targeted was only recently converted into an arms factory. Israel has carried out repeated air and missile strikes against government forces and their Iran-backed allies in Syria since the war broke out in 2011. It rarely comments on individual military operations. A US-led coalition fighting the remnants of the ISIS group in Iraq and Syria has also carried out strikes against pro-Iran fighters in Syria in the past. Wednesday's attack targeted a part of Deir Ezzor that is home to residences of top Iranian commanders and senior officers of Lebanon's Hezbollah movement, as well as an Iranian hospital for cholera patients, Abdel Rahman said. Pro-Iran factions aligned with the Syrian government, including Iraqi groups and Hezbollah, are heavily deployed south and west of the Euphrates River which bisects Deir Ezzor province. Syrian state media said a landmine planted by ISIS group "terrorists" exploded in the same neighborhood, killing three and wounding seven. "Three citizens were killed and seven others injured" in the explosion, state news agency SANA reported. It published photographs of the aftermath of the blast that showed extensive damage to a building and a truck. The attack followed a series of unclaimed drone strikes on January 30 that targeted a suspected Iranian weapons convoy in the province and killed 11 people, including a pro-Iranian commander, the Observatory said at the time. The 25-truck convoy had been targeted three times in less than 24 hours, a Syrian official had told AFP, denying the trucks carried weapons. The conflict in Syria started in 2011 with the brutal repression of peaceful protests and escalated to pull in foreign powers and global extremists. The war has killed nearly half a million people and forced around half of the country's pre-war population from their homes.