DAMASCUS - Syrian government forces on Thursday retook a key town on the outskirts of the capital Damascus after fighting for months to recapture it from rebels, a military source and state television said.The news was confirmed by the Syrian Observatory for Human Rights monitoring group."Today the Syrian Arab Army took complete control of the town of Mleiha," a military source in Damascus said.State television meanwhile broadcast live from the town, showing streets with holes punched through homes by rockets and twisted metal from telephone line poles. Mleiha lies southeast of the capital and has been a key flashpoint in the fighting around Damascus.Government troops, backed at times by fighters from the allied Lebanese Shiite group Hezbollah, have been battling there since April.The area has been under siege for more than a year, and under near-constant bombardment by government forces. The chief of Syria's air defence forces, General Hussein Isaac, was killed in fighting there in May.Mleiha is strategic because it lies next to the key rebel bastion of Eastern Ghouta outside the capital, which the regime has also struggled to recapture."Taking back Mleiha would allow the regime to protect parts of Damascus from rebel rocket fire on the capital," Observatory director Rami Abdel Rahman said. "It is also the gateway to Eastern Ghouta," he added.While the government retains firm control over Damascus, rebels have several rear bases around the city, from which they regularly launch rockets.Elsewhere in Syria, the Observatory said Islamic State militants had beheaded at least nine opposition fighters on Wednesday night, after seizing several northern villages.The extremist group, which has been battling other Islamist and moderate opposition groups in large parts of Syria, took control of eight villages between the Turkish border and the northern Syrian city of Aleppo on Wednesday.The Observatory said at least 40 rebels were killed in the fighting, along with 12 IS militants.Another 50 rebels were taken prisoner by the militants, and the Observatory said on Thursday that nine had been beheaded in Akhatarin, which was captured in the IS advance.IS grew from Al-Qaeda's one-time Iraqi branch and originally fought alongside Syria's rebel groups, but it has been denounced by Al-Qaeda's leader and other opposition groups have turned against it.In January, a coalition of Islamist and moderate opposition fighters began battling IS, forcing it to retreat for a time to its stronghold in Raqa province.But with the capture of large swathes of Iraqi territory across the border, as well as heavy military equipment, the group has since managed to regain some lost ground in Syria.