An alliance of Syrian rebel forces, the Southern Front alliance, have taken control of "Brigade 52", an army base belonging to the Syrian regime, in the northern countryside outside Daraa.
Syria's Southern Front rebel alliance has taken control of the 52nd Brigade army base after clashes and intense shelling, the UK-based Syrian Observatory for Human Rights monitoring group said on Tuesday.
Opposition fighters were able to break into the brigade's command headquarters, Ahmad Qura Ali, spokesman of the Ahrar al-Sham Islamic Movement, told al-Araby al-Jadeed.
Syria's official news agency, SANA, has yet to report on the capture of the base - a blow to the Damascus regime.
Several armed factions on Tuesday announced the launch of the "battle of retribution", which aimed to take control of Brigade 52, considered to be the Syrian regime's largest base in Daraa province.
The base lies near a major highway running from Damascus to Syria's southern border with Jordan, and is also near Daraa's frontier with neighbouring Sweida province, which is largely regime-controlled.
The armed groups understood to have united to capture the base from Syrian troops are the Jaish al-Islam, Lions of War unit, al-Jaish al-Awwal, Jund al-Malahim, al-Fatiheen, al-Hirak and Ahrar al-Sham.
Regime troops and their allied militias suffered casualties and two of their vehicles were damaged. Eight opposition fighters were also killed. including a field commander, according to the opposition-leaning Syrian Observatory for Human Rights, which relies on a wide network of sources inside Syria.
The loss of the Brigade 52 base follows earlier defeats for the regime in Daraa, where it last month lost control of the Nasib border post, the last crossing with Jordan under Damascus' control.