Members of Syria's Druze minority have helped halt a rebel attack on an army base in the south, responding to a call to arms to confront insurgents including al Qaeda's Nusra Front who are trying to build on gains against President Bashar al-Assad. The Syrian Observatory for Human Rights, a UK-based organization that tracks the war, said on Friday rebels had been driven from the base which they had partly captured on Thursday by air strikes and Druze fighters from nearby Sweida city. A Druze leader from Sweida said young men from Sweida had helped recapture the disused al-Thala airbase, responding to a call to arms issued on Tuesday. A rebel leader confirmed that the government side had sent reinforcements to the base. The Druze community is spread between Syria, Lebanon, Israel and Jordan. Their religion is an off-shoot of Islam incorporating elements of other faiths and is viewed as heretical by al Qaeda and Islamic State. ADVERTISING Some Druze leaders have warned of an existential threat facing their kin after Nusra Front fighters shot dead 20 people in a Druze village in northwestern Syria on Wednesday - an incident ignited by Nusra's attempt to confiscate a house. Insurgents battling Assad in southern Syria include the Nusra Front but also groups that do not share its jihadist ideology and are trying to calm Druze fears. They say Assad, a member of the minority Alawite faith, is seeking to exploit those fears to shore up support. Druze leaders had issued a call to arms in Sweida this week, alarmed by advances from the west and also from the east, where Islamic State has been attacking the army. Their role was key in repelling the attack on the base, said Rami Abdulrahman, who runs the Observatory. "If they hadn't mobilized, (the insurgents) wouldn't have been repelled," he said. "There is a rebel retreat." Bashar al-Zoubi, the head of one of the rebel groups attacking the base, said it was still in government hands on Friday. The Druze leader, Sheikh Abu Khaled Shaaban, said young men from Sweida had deployed in several areas including the airport under the umbrella of the National Defense Force and "popular committees" that are battling alongside the Syrian army. State television also said dozens of Suweida residents joined the army and NDF fighters. "Matters are heading toward calm and complete control of the situation," Shaaban told Reuters by telephone from Syria. Since March, an array of insurgent groups have gained ground from Assad in the northwest, the east and the south. The southern rebels, operating in a region just 100 km (60 miles) from Damascus, seized a major army base on Tuesday in Deraa province, building on victories including the capture of the Nasib border crossing with Jordan. Fears for Syria's Druze have been voiced among the Druze communities in both Lebanon and Israel in recent days. Druze in Israel have been lobbying for arms to be sent to Syria, a U.S. official has said. Lebanese Druze politicians aligned with the Syrian government have also called for the Druze in Syria to be sent weapons, describing their situation as an existential threat. But Walid Jumblatt, a Lebanese Druze leader who backs the uprising against Assad, has urged the Druze of Sweida to reconcile their differences with the Syrian opposition.